Atmósfera

Influence of teleconnections on observations and projections of hydroclimatic extremes caused by tropical cyclones in the arid climate of Baja California Sur (edited by Dr. Matilde Rusticucci)

Brenda Liliana Bello-Jiménez — 2024-04-26

This study focuses on identifying modulations by large-scale synoptic, inter-annual, and decadal oscillations on the extreme rainfall in the state of Baja California Sur, and provides statistical models to forecast future evolution. The region is arid, with 70% of precipitation from July to October, and is affected by tropical systems that may lead to moderate and even intense precipitation. Seven clusters were obtained using the Ward method applied to quality-controlled climatological data from 1950 to 2014. Normalized extreme precipitation (95th percentile) shows an overall increase in the last decades (1995-2004 and 2005-2014), with total values much larger than in any of the previous 50 years. Multivariate linear models (MLMs) were developed based on indices for the Pacific Decadal Oscillation (PDO) and El Niño-Southern Oscillation (ENSO) in Region 3.4, which were shown to modulate extreme precipitation. The MLM based on PDO, ENSO, and the fraction of tropical cyclones (TC) within a radius of 300 km to the peninsula (M4), has a better correlation with observed rainfall than the historical simulations of the Coupled-Model Inter-comparison Project version 5 (CMIP5) models; moreover, M4 outperforms all other MLMs in six of the seven clusters. Projections were evaluated based on the MLMs and CMIP5 simulations under scenarios RCP4.5 and RCP8.5 for mid- and long-term horizons. Model M4 projects more extreme events than CMIP5, and all MLM projects negative trends in extreme precipitation from 2041 to 2100 under RCP8.5. This study provides valuable information on future extreme precipitation in an arid region in the presence of steep topography, which could result in potential damage to ecosystems and infrastructure.

Chemical composition and trajectories of atmospheric particles at the Machu Picchu Peruvian Antarctic scientific station (62.09º S, 58.47º W)

Daniel Alvarez-Tolentino — 2024-04-25

Antarctica is a remote and relatively pristine region, but the regional transport of aerosols may be a source of pollution, especially in the Antarctic Peninsula. Few studies have characterized atmospheric aerosols and evaluated the contribution of their emission sources. The Peruvian Antarctic research station Machu Pichu (ECAMP, by its Spanish acronym) is located on King George Island in the Antarctic Peninsula. During February 2020, atmospheric particulate mass (PM₁₀and PM_2.5) was sampled and analyzed to characterize its elemental composition and was supplemented by measurements of equivalent black carbon and aerosol size distributions. Chemical elements were analyzed by inductively coupled plasma mass spectrometry (ICP-MS), multivariate techniques, and enrichment factors. The most abundant elements in PM₁₀ and PM_2.5were Na, Fe, Mg, and Si, with the most important local sources being marine (Na, Mg, Mn, Ca) and crustal (Fe, Al, P). Sources of weathering (Ba and Si) from glacial thawing and sources of combustion linked to the use of oil (V) and emission of black carbon were recorded. Air mass back-trajectory analysis using the HYSPLIT model helped identify external sources of particulate matter in the air masses reaching the ECAMP site. Overall, this study supports the growing evidence of the anthropogenic impact of distant and local sources on the white continent.

Simulation and synoptic investigation of a severe dust storm originated from the Urmia Lake in the Middle East

Nasim Hossein Hamzeh — 2024-04-22

Dried lake beds are one of the largest sources of dust in the world, causing environmental problems in the surrounding areas. In this study, the desiccated Urmia Lake was the primary source of dust for all nearby synoptic stations during the April 24-25, 2017 dust episode. Synoptic analysis revealed that the heavy dust storm was triggered by a strong Black Sea cyclone and a low-pressure system over central Iraq in conjunction with a vast high-pressure system. HYSPLIT-based trajectory analysis showed that high PM₁₀ recorded over the Urmia Lake region on April 23-26, 2017, influenced western Azerbaijan, the south of the Caspian Sea, southwestern Kazakhstan, northwestern Uzbekistan, and western Turkmenistan. The dustiest air masses (PM₁₀ > 400 µg m^–3) affected the south of the Caspian Sea and western Azerbaijan. Furthermore, the WRF-Chem model was run to evaluate the spatial distribution of dust particles in the study region. The vertical profile revealed that the simulated dust concentration ascended to 5 km from the lake. The WRF-Chem dust schemes accurately simulated dust propagation and the vertical dust profile over Urmia Lake; however, the AFWA and GOCART dust schemes showed that PM₁₀ fluctuating changes were earlier than the measured surface PM₁₀ at five stations around Urmia Lake on April 23-26, 2017. Furthermore, the maximum amount anticipated by the model simulation was 12 h earlier than the maximum surface mass concentration of measured PM₁₀ at the stations throughout the period.

Comparison of different drought monitoring indices in different climatic conditions in Iran

Samira Rahnama — 2024-04-11

This study evaluates drought in different climate zones (Rasht, Shiraz, and Birjand) in Iran, using meteorological, agricultural, and remote sensing drought indices. For this purpose, NDVI, SAVI, and SR were extracted from Landsat images for 2002 and 2014-2020. Then, these indices were compared with the SPI, SPEI, and PDSI. The results indicate an increase in drought and a decrease in vegetation cover in the study area. In Rasht, where the vegetation cover is high, NDVI and SAVI were equal. In Shiraz and Birjand, where the soil effect is more significant, the distance between these two indices increased, which shows that SAVI performs better than NDVI for Shiraz and Birjand. The results also show that the drought severity could grow with decreasing rainfall and more water demand due to temperature increases, according to SPI, SPEI, and PDSI criteria. The comparison of drought indices showed that the highest correlations were between NDVI plus SAVI and SPI in Rasht, SR and SPEI in Shiraz, and NDVI and SPEI in Birjand. Based on the results of the Mann-Kendall test, the increasing trend of drought in the studied area is confirmed based on the SPI, SPEI, and PDSI. Therefore, it is suggested that remote sensing techniques combined with drought indices can be considered a suitable tool for optimal management of water resources, land use planning, and reduction of costs due to drought.

Observed interannual variability and projected scenarios of drought in the Chorotega region, Costa Rica

Melissa Ríos-Solano — 2024-03-29

The observation-based analysis of drought development in the Chorotega region showed that, despite the area being relatively small, agricultural drought exhibits high spatial variability across the region. However, the lack of net radiation data hinders the capacity to provide reliable estimates of evapotranspiration (ET), affecting the assessment of drought occurrence, since its propagation across the hydrological system is very sensitive to the ET estimation method. The coarse resolution of satellite-derived Normalized Difference Vegetation Index (NDVI) products and the lack of information on irrigation in agricultural areas limits the ability to properly establish a relationship between drought and vegetation response. Based on the observations, the most prominent precipitation deficits occur between September and October (–100 mm on average), showing that changes in the large-scale circulation are responsible for the impact of severe drought in the region. In agreement with previous studies, El Niño-Southern Oscillation (ENSO) is the main modulator of the drought severity, with the warm ENSO phase favoring an enhanced drought development and its influence being more significant between August and October, displaying correlations greater than –0.6. The climate change projections under RCP4.5 and RCP8.5 scenarios suggest the intensification of drought events in the Chorotega region at mid-century, with the Tempisque-Bebedero basin being the most affected area in terms of precipitation decrease and warming. The projected scenarios correspond to an increase of 1 ^oC for mean temperature and more of 2 ^oC for minimum and maximum temperature in the 2050 horizon, as well as a decrease of 400 to 800 mm for annual precipitation under both RCPs.

Small-scale variation of atmospheric dynamics applying chaos theory, case study

Arquímides Haro Velasteguí — 2024-03-26

Characterization and knowledge of the variability of atmospheric dynamics on a small scale in the city of Riobamba, Ecuador, are achieved through the chaos theory. Meteorological data is taken every hour during four years, including variables such as wind speed, wind direction, incident radiation, temperature, and humidity, from the ESPOCH, SAN JUAN, and QUIMIAG weather stations in the canton of Riobamba. The van Ulden and Hostlang models are used to calculate the Obukhov length, surface heat fluxes, and latent heat flux. The chaos theory is applied to study the variation of atmospheric microdynamics. The Lyapunov coefficients, Kolmogorov-Sinai entropy, and Kaplan-Yorke fractal dimension are determined. Before analysis, noise reduction is necessary due to the lack of correlation, especially in the Obukhov length. This research follows a longitudinal design and employs quantitative and explanatory methods based on data analysis, statistical-mathematical techniques, and inductive-deductive approaches. The results indicate a highly variable system, reflected in a high number of Lyapunov coefficients, fractional dimensions, and entropy variations. The microdynamic parameters exhibit hyperchaotic behavior, as indicated by the presence of more than one positive Lyapunov coefficient. The variables also demonstrate a fractional fractal dimension, highlighting the irregularity in the geometric representation of the system.

Studies on airborne microbiota in Mexico, a review

Óscar Omar Álvarez-Rivera — 2024-03-14

Airborne microbiota has garnered increasing interest in recent decades, not only because of its role as carrier of pathogenic microorganisms and its involvement in the deterioration of man-made objects, buildings, and food but also because of its participation in atmospheric processes and its content of microorganisms important for biogeochemical cycles in different ecosystems. In order to understand and comprehensively analyze existing studies on airborne microbiota in Mexico, a systematic review was conducted utilizing Web of Science and Google Scholar as search tools. The information found in the 35 identified publications was systematically organized, including title, study location, sampling method, laboratory approach, identification method, and organisms found. This information was then ordered into three sections: bibliometric analysis, employed methodologies, and main findings. Through this work, it was revealed that the studies were carried out in 14 out of the 32 states of Mexico, with Mexico City standing out with 17 articles. Three methodological approaches were identified: microbial cultures (77% of the studies), microscopy (11.5%), and metagenomics (11.5%). The studies predominantly focused on state capitals or densely populated cities, making the identification of potentially pathogenic organisms from humans, animals, and plants, of particular interest. This comprehensive review lays the foundation for proposing compelling avenues of future research, aimed at advancing our comprehension of airborne microbiota in Mexico.

Comparison of COSMO and ICON-LAM high-resolution numerical forecast for Romanian territory: Case studies and evaluation

Amalia Iriza-Burca — 2024-03-11

This paper aims to offer the first detailed inter-comparison of the performance from the numerical weather prediction models Consortium for Small-scale Modeling (COSMO) and Icosahedral Nonhydrostatic General Circulation Model, Limited Area Mode (ICON-LAM), integrated for the Romanian territory at the horizontal resolution of 2.8 km. As the ICON numerical model is set to replace COSMO, a comparison is carried out between the operational configurations of the two models. First, two cases with severe weather (strong atmospheric instability, observed heavy precipitation, and strong wind) are analyzed: February 3-6, 2020 (heavy precipitation [snow] and very strong wind) and May 3-5, 2020 (heavy precipitation). This is followed by a statistical inter-comparison between the two models for the summer of 2020 (June, July, August). A statistical evaluation of the forecast quality from the two models is performed objectively, through statistical scores computed using surface observations from all available meteorological stations on the Romanian territory. Stratifications depending on station altitude and location are carried out, with emphasis on stations of particular interest, depending on the evolution of the synoptic situation. Following the statistical evaluation, results for the precipitation forecast do not show significant improvement in favor of either model. However, ICON-2.8 km mostly outperforms COSMO-2.8 km for surface parameters.

Quantifying of surface urban heat island intensity in Isfahan metropolis using MODIS\Terra\LST data

Majid Montazeri — 2024-03-07

Heat island characteristics depend on the background climate of the site where the city is located. Therefore, an index was defined for the Isfahan metropolitan area to quantify the surface urban heat island intensity. This new index is based on the representative pixels of urban and non-urban areas. For this purpose, MODIS land cover type product (MCD12Q1) data were used to distinguish between urban and non-urban areas. Also, data from the MODIS/Terra land surface temperature product (MOD11A1) from 2000 to 2018 were utilized for daytime and nighttime to study the surface heat island intensity. Then, the representative pixels of urban and non-urban areas were identified using the spatial correlation method, and the heat island index was calculated for the metropolitan area of Isfahan. The study showed that the frequency distribution of the nighttime heat island index follows a normal distribution and is often 3.5 to 4º K above the temperature of the surrounding areas of the city. The 365-day floating mean of the surface urban heat island reveals that this index has increased in recent years. The research of temporal behavior showed that the intensity of the surface urban heat island reaches its maximum in January and becomes weaker in summer, while the survey of spatial behavior showed that the core of the surface urban heat island extends towards downtown areas, where the oldest part of the city is located.

Trend analysis and forecast of annual precipitation and temperature series in the Eastern Mediterranean region

Vasileios D. Sakalis — 2024-02-15

The present study aims to examine the current trend of annual precipitation and temperature series referred to the Eastern Mediterranean basin on a national basis, including the annual variability of sea surface temperature anomalies and the connection effect with the North Atlantic Oscillation and the Mediterranean Oscillation indices (NAOI and MOI, respectively). The period under consideration is mainly the last 32 years, from 1990 to 2021. Additionally, the prediction of monthly and yearly temperature and precipitation series, based on the autoregressive integrated moving average model on a national base, for the next four or eight years, is another interesting feature of the present study. Results indicate rising trends in the annual precipitation during 1990-2021, mostly non-significant and significant warming trends in the annual temperature, including sea surface temperature. The NAOI is highly correlated mostly with annual temperature, whereas the MOI does not affect the variation of annual precipitation and temperature. The results of the present study are in general agreement with the results of available studies in the literature, and they could be of high interest to national authorities and environmental unions/organizations, to help decision-makers face climate change.

Carbonaceous particles and PM2.5 optical properties in Mexico City during the ACU15 campaign

Naxieli Santiago-de la Rosa — 2024-01-24

We measured the optical properties of aerosols with two photoacoustic spectrometers operating at 532 and 870 nm wavelengths and sampled PM_2.5 to analyze the organic carbon (OC) and elemental carbon (EC) content. The measuring site was in the southwest corner of Mexico City. We sorted the data by OC/EC ratios and calculated four mass absorption efficiencies (MAEs) for each wavelength with linear regressions. The MAEs ranged from 2.27 to 19.75 and 2.03 to 15.26 m² g^–1 at 532 and 870 nm, respectively, with determination coefficients above 0.88, showing that the amount of OC modifies the absorption properties of particles, sometimes underestimating or overestimating the black carbon concentration. It is possible to choose the MAE based on the daily median O₃ concentration when there is no information about the EC and OC composition.

Solar PV technologies selection for the design of photovoltaic installations in Mexico based on the analysis of meteorological satellite data from the region

Ricardo Miranda-Jiménez — 2023-12-08

Mexico’s expansive territory spans diverse climatic conditions, which directly influences the selection of commercial photovoltaic technologies. This study utilizes solar irradiance, temperature, and cloud index data (derived from satellite sources) to generate a suitability map for commercial solar panel technologies through the Analytical Hierarchy Process-Geographical Information Systems methodology. The map illustrates that chalcopyrites and cadmium telluride emerge as the most suitable technologies in 47.12% of the national territory. Following closely behind is amorphous silicon, covering 30.45%, while monocrystalline and polycrystalline silicon account for 22.43%. The primary objective of this paper is to guide the proper selection of solar panel technology types that align optimally with Mexico’s climatic conditions. This strategic approach aims to strengthen the planning and viability of photovoltaic solar energy projects nationwide.

Variability, cycles, and trends of mean air temperature north of Colombia

Andrea Patricia Manrique-Cantillo — 2023-12-07

Climate variability is of global interest due to its socioeconomic and environmental effects on the world’s population. In Colombia, temperature changes affect food security, especially for the most vulnerable people in the Caribbean region. We analyzed monthly air temperature in northeastern Colombia (Cesar, La Guajira, and Magdalena departments). We reconstructed time series with missing data using nonlinear principal component analysis. Subsequently, temporal variability, associations with events of climatic variability, and temporal trends were evaluated. Periodicity analyses indicate the dominance of annual variability, although statistically significant associations with periods between 3 and 7 years show the influence of El Niño-Southern Oscillation (ENSO) events. The Spearman correlation coefficient with N = 360 and 95% significance shows a better association with the Multivariate ENSO Index (r_{sp mean} = 0.38) and the Southern Oscillation Index (r_{sp mean} = –0.32). The multi-year monthly analysis shows positive trends, with maximum values between March (1.04 ºC month^–1), and June (1.07 ºC month^–1) in the valley of the Cesar department, and a minimum in March, at the northernmost La Guajira (0.2 ºC month^–1).

Exploring the academic perceptions of climate engineering in developing countries

Athar Hussain — 2023-11-21

The idea of climate engineering still remains elusive, particularly in several of those developing countries that are most affected by climate change. This knowledge gap can be addressed by knowing the perception of climate change and then introducing and getting feedback on its modification via climate engineering, from the select group of developing countries. Building upon an earlier attempt to achieve these aims, a new group of three developing countries in the global South (Pakistan, Nigeria, and Kenya) is selected to examine their perspective via a total of more than 1000 responses. Descriptive and inferential results indicate that there are significant differences within the global South on awareness of global warming and climate engineering, as well as on the deployment of sulfate aerosols as a measure to delay the harshest effects of global warming.

Subsurface temperature change attributed to climate change at the northern latitude site of Kapuskasing, Canada

Ivan L. Novara — 2023-11-13

Subsurface temperatures have been measured in different regions of the world, usually near the surface up to a depth of about a hundred meters. In this work a forward model calculation for a Northern Hemisphere soil temperature site at Kapuskasing, Canada, is presented, employing the solution of the differential equation of heat conduction through a semi-infinite homogeneous solid, subject to surface boundary conditions determined by surface air temperature. In this way, a detailed analysis is made of the subsurface temperature as a function of ground depth and for the time interval ranging from 1970 to the future (including the next century), for different scenarios of climate change. From these results, it was possible to determine the following characteristic quantities: (a) the depth where the surface perturbation (practically) finishes (in the range of about 180-200 m); (b) the depth where the subsurface temperature changes its slope from negative to positive; (c) the temperature change at the surface for the years where data exist; (d) the thermal gradient at steady state in the starting year (1880); (e) the temperature differences extrapolated at surface and at a 20 m depth, this last value corresponding to the depth at which seasonal and diurnal temperature variations are negligible; (f) the heat flow at surface to the inner part of the soil attributed to climate change, and (g) the temperature changes at surface for the 100 years interval (1980-2080) and mainly for the next century (2080-2180), for each site and for each IPCC Representative Concentration Pathway (RCP) scenario. As an example, the impact of the change in mean annual soil temperature due to global warming in near-surface geothermal energy is described.

Development of a CFD model to simulate the dispersion of atmospheric NH3 in a semi-open barn

Guillermo Alfonso de la Torre-Gea — 2023-11-03

The dispersion of atmospheric NH₃ constitutes the most common passive polluting system in cattle stables. Although the studies carried out through computational fluid dynamics (CFD) are focused on improving the environmental conditions in situ to increase the productivity of stables, they do not refer to determining the environmental impact of NH₃ emissions into the atmosphere. This work evaluated the distribution of the NH₃ flux inside a barn using CFD and its relationship with environmental conditions through probabilistic analysis by the K2 algorithm. The initial data on environmental conditions were wind speed and direction, maximum temperature, and humidity from the nearest weather station in a region characterized by hot weather conditions during summer. The vertical trajectory was used to analyze the impact of long-range transport on the spatial distribution, where 75% is between 0 and 5 m in height, and 25% is between 10 and 20 m outside the eaves. The work concluded that temperature is the main parameter of influence.

Using a hybrid approach for wind power forecasting in Northwestern Mexico

Yanet Diaz-Esteban — 2023-10-30

Wind energy is an important renewable source that has been considerably developed recently. In order to obtain successful 24-h lead-time wind power forecasts for operational and commercial uses, a combination of physical and statistical models is desirable. In this paper, a hybrid methodology that employs a numerical weather prediction model (Weather Research and Forecasting) and a neural network (NN) algorithm is proposed and assessed. The methodology is applied to a wind farm in northwestern Mexico, a region with high wind potential where complex geography adds large uncertainty to wind energy forecasts. The energy forecasts are then evaluated against actual on-site power generation over one year and compared with two reference models: decision trees (DT) and support vector regression (SVR). The proposed method exhibits a better performance with respect to the reference methods, showing an hourly normalized mean absolute percentage error of 6.97%, which represents 6 and 13 percentage points less error in wind power forecasts than with DT and SVR methods, respectively. Under strong synoptic forcing, the NN wind power forecast is not very accurate, and novel approaches such as hierarchical algorithms should be employed instead. Overall, the proposed model is capable of producing high-quality wind power forecasts for most weather conditions prevailing in this region and demonstrates a good performance with respect to similar models for medium-term wind power forecasts.

Performance evaluation of the WRF model under different physical schemes for air quality purposes in Buenos Aires, Argentina

Solange E. Luque — 2023-10-05

This work presents the performance evaluation of the Weather Research and Forecasting (WRF) model to estimate surface wind speed and direction, air temperature, and water vapor mixing ratio considering 22 configurations at high spatial resolution (1 km) during one week in winter and one week in spring, in order to determine the best-performing schemes for air quality purposes in the Metropolitan Area of Buenos Aires, Argentina. Results show that the use of urban schemes mostly affects wind speed and temperature. The single-layer urban canopy model (UCM) coupled with the Boulac planetary boundary layer (PBL) scheme exhibits the best results for wind speed. Wind direction and water vapor mixing ratio are more sensitive to the land surface model scheme, with results slightly improving with the Noah-MP land surface model. Wind speed and direction errors are larger when the former is lower. When removing from the analysis wind speed values below 2.6 m s^–1 for the winter week and 3.1 m s^–1 for the spring week, the root mean square errors for wind direction decreased between 50 and 72% of the original value, depending on the configuration and week. Overall, under the studied conditions, configurations including Noah-Mp land surface model or the combination of a simple UCM with BouLac PBL are suitable for air quality applications, as they reproduce both temperature and water vapor mixing ratio relatively well, with errors below 10% and Correlation values above 0.7, and are the best performing configurations for wind direction and speed, respectively.

Atlantic and Pacific sea surface temperature correlations with precipitation over northern Mexico

Regina Mijares-Fajardo — 2023-09-25

Three main sea surface temperature (SST) oscillations in the Atlantic and Pacific oceans have shown to play a key role in modulating rainfall variability over northern Mexico. Nevertheless, only a few studies have explored these teleconnections under a climate classification approach. In this study, the effects of the Pacific Decadal Oscillation (PDO), the Oceanic El Niño Index (ONI) and the Atlantic Multidecadal Oscillation (AMO), over precipitation in dry and semi-dry areas of the Baja California peninsula and the state of Tamaulipas are analyzed for the period 1951-2021. Pearson and Spearman correlations are compared and proven to have equivalent results despite the different physical conditions of the two territories. The results show several statistically significant correlations indicating that for the study regions, the correlation is negative throughout the year between the Standardized Precipitation Index (SPI) and AMO in latitudes above 28º N, while it is negative (positive) during the months of January-April (October-November) in lower latitudes. Simultaneously, the correlation is positive between SPI and ONI/PDO in eastern and western regions of northern Mexico, and it is negative between SPI-ONI and SPI-PDO in the months of August-September over the eastern side. The information generated throughout this study, in conjunction with the understanding of regional climate dynamics, can help to comprehend with greater certainty the effects of these teleconnections.

Urban atmospheric humidity excesses and deficits in two Mexican metropolises: Guadalajara and Puebla

Adalberto Tejeda-Martínez — 2023-09-25

Comparative studies of atmospheric humidity between urban and suburban and urban-rural environments are scarce, and their results are very scattered and inconclusive. In this paper, we compare differences in atmospheric temperature, relative humidity and absolute humidity measured at the limits between the urban canopy and the boundary layer in two elevated metropolises in Mexico: Guadalajara and Puebla. Results show that variations in relative humidity contrasts between different environments have an inverse relationship with the temperature variations. In Guadalajara, the urban excesses of absolute humidity are predominant from May to September. In Puebla the urban-suburban contrasts are lower than in Guadalajara, following a daily cycle and being negative between noon and 18:00 LT. From March to September urban-rural differences in Puebla are positive between 10:00 and 18:00 LT, and weak during the nocturnal period.

Distribution changes of the toxic mushroom Amanita phalloides under climate change scenarios and its potential risk over indigenous communities in Mexico

Abril Villagrán-Vázquez — 2023-09-25

Amanita phalloides is a native European deathly ectomycorrhizal mushroom that was introduced to North America and has been expanding its distribution during the last decades. This species is morphologically similar to wild edible mushrooms and if its distribution expands to Mexico, it could represent a risk in terms of food security for local communities. The aim of this study was to evaluate the potential climatic suitability that exists for A. phalloides in North America and overlay it with the distribution of mycophilic communities in Mexico under a baseline climatic scenario and climate change scenarios. To find climatic suitability we modeled its potential distribution with the algorithm that had the best predictive power after pilot test (MaxEnt) using species presences and eight climatic variables chosen with biological and statistical criteria. We worked with CanESM5 because it is one of the best models to simulate climate in North America and SSP5-8.5 scenario in order to be consistent with the precautionary principle. Our results suggest that even when the species has not yet been registered in Mexico, when using European records to model, this country presents 33.61% of climatic suitability for this species under the baseline scenario, potentially affecting about 70% of indigenous communities which are the main consumers of edible mushrooms. Under climate change scenarios, an increase in climatic suitability is expected in Mexico, while decreases are expected in United States and Canada. When using North American records to model, almost no climatic suitability is found in Mexico; however, the implementation of warning campaigns in Mexico is still needed.

Satellite data geoprocessing to estimate PM2.5 over the Megalopolis of Central Mexico

Marco Antonio Mora-Ramírez — 2023-09-25

The Megalopolis of Central Mexico experiences high levels above the Official Mexican Standard (NOM) of PM_2.5, leading to various respiratory diseases ranging from acute symptoms to chronic illnesses such as asthma and lung cancer. It is crucial to measure PM_2.5 levels accurately to warn the public about the risks of exposure to particulate matter. Unfortunately, the Megalopolis of Central Mexico has a shortage of monitoring sites, limiting data availability. This study addresses this issue using satellite data to develop a multiple linear regression model. Our model uses aerosol optical depth (AOD), relative humidity (RH), temperature (T), the planetary boundary layer height (PBLH), and the normalized difference vegetation index (NDVI) as independent variables to estimate PM_2.5 concentrations in the region under study. The relationship between AOD and PM_2.5 concentrations was found to be strongly influenced by RH and T. However, this effect is compensated for by a low PBLH (< 400 m), which enables AOD and PM_2.5 measurements to be similar in magnitude. Our findings have important implications for estimating PM_2.5 concentrations using satellite data. This study could help improve air quality monitoring in the Megalopolis of Central Mexico by providing more spatial and temporal data on particle concentrations in the atmosphere.

El Niño-Southern Oscillation diversity and its relationship with the North Atlantic Oscillation – Atmospheric anomalies response over the North Atlantic and the Pacific

Gabriel Santiago Gutiérrez-Cárdenas — 2023-09-25

To explore the impacts of El Niño-Southern Oscillation (ENSO) on the North Atlantic Oscillation (NAO), the linear correlation among the indices of each oscillation was investigated. The indices Niño 1+2, Niño 3, Niño 3.4, Niño 4, ONI, SOI, BEST, TNI and MEI were used to represent the ENSO, besides the NAO index. The analysis considers the ENSO diversity in its spatial structure. The results show that when years with Eastern Pacific (EP) La Niña events were omitted, the linear correlation increased concerning other scenarios. This means that NAO responses for the Central Pacific (CP) ENSO tend to be linear, but seemingly they are not so for EP ENSO, which explains why the ENSO/NAO relationship has been difficult to identify and predict. The TNI-NAO relationship had the highest correlation values, followed by NAO-El Niño 4, whilst NAO/El Niño 1+2 and NAO/El Niño 3 showed the lowest coefficients. The results also confirmed that the atmospheric dynamics over the North Atlantic have a more linear teleconnection to the West and Central Pacific than to the Eastern Pacific. Changes in deep convection, atmospheric circulation, and vorticity are discussed like possible mechanisms that trigger the changes in impacts over the North Atlantic and other locations. The composite anomalies map also showed the contrast in the effects of both events and the importance of considering those differences when modeling ocean dynamics.

Structural change points of NDVI in Mexico driven by climate oscillations

Oscar O. Díaz — 2023-09-25

Based on the climatology of air temperature, precipitation, and the normalized vegetation index (NDVI), a regionalization of Mexico for the rainy season is presented through a non-parametric clustering algorithm known as DBSCAN. Thirty years of data, spanning from 1984 to 2013, are used to detect structural change points with the Mann-Kendall and Pettitt non-parametric tests applied on the NDVI, mean daily precipitation, 99th percentile precipitation, and mean daily air temperature. The relative predictive importance of the parameters examined was estimated using a Machine-Learning Random Forest algorithm that allows establishing a connection between changes in the NDVI and changes in air temperature, average precipitation, and extreme precipitation for some regions. Modulation by large-scale climate phenomena, such as the Atlantic Multidecadal Oscillation (AMO) and the Pacific Decadal Oscillation (PDO), as well as interannual modulation by El Niño/Southern Oscillation (ENSO) are explored. Structural change points in the series appear to be modulated mainly by the phase shift of the AMO and those of the ENSO and PDO in 1997.

Evaluation of the SACZ index as a prognostic tool based on GFS forecasts

Louise da Fonseca Aguiar — 2023-08-01

The South Atlantic Convergence Zone (SACZ) is an atmospheric phenomenon typical of summertime where a band of nebulosity causes intense or persistent rainfall in many regions of Brazil. SACZ episodes can be responsible for many natural disasters. Besides, the impacts of rainfall on water availability and consequently on the energy sector are extensive. The main objective of this study was to investigate the implementation of the SACZ index as an objective forecasting tool using input data from the Global Forecast System (GFS) model. Initially, we compared the index with the SACZ events identified by the Center for Weather Forecasting and Climate Studies (CPTEC ) from 2017 to 2021. Results showed that the index represented all events identified SACZs by CPTEC. Finally, we used data from the GFS 0.25 Degree from 2017 to 2021 to calculate Accuracy, Probability of detection, and False alarm ratio to evaluate the SACZ index as a prediction tool. Three thresholds are defined for the binary classification of a possible SACZ event. Results showed that above the most sensitive threshold (h1), within 10 days in advance, the sign of a possible SACZ can be detected. For the intermediate threshold (h2), a forecast of 96 h can detect a sign. For the most specific threshold (h3), the index can detect the event within 72 h in advance with a probability of detection of almost 90%. The SACZ index proved to be an efficient tool for detecting the dynamics of the phenomenon and can be used to assist operationally and in decision-making.

Modeling tropical storm Elsa: Flood map simulation using multisensory precipitation in Connecticut

Juan M. Stella — 2023-08-01

A flood map simulation in the Fenton River watershed, Connecticut, was conducted for Tropical Storm Elsa occurred in early July 2021, using Multi Radar Multi Sensor-Quantitative Precipitation Estimation (MRMS-QPE) as input to force the Hydrologic Engineering Center-Hydrologic Modeling System (HEC-HMS) to simulate discharges in the mainstream of the watershed. The simulated discharges were calibrated using observed discharges at the Old Turnpike Bridge USGS station, and they were used to force a Hydrologic Engineering Center-River Analysis System (HEC-RAS) 2D model of the Fenton River watershed. The simulated stages were calibrated using observed stages at Old Turnpike Bridge USGS station to simulate flood maps in the mainstream of the watershed. The resulting use of HEC-HMS and HEC-RAS 2D models coupled with MRMS-QPE precipitation shows that these models set up is user-friendly. The model shows stability and the capacity to simulate flood maps along the whole mainstream of the Fenton River with good accuracy.

Dense fog simulation in southern Brazil using the WRF model with high spatial resolution

Judith Rodrigues Cardoso — 2023-08-01

Fog is an atmospheric phenomenon that reduces horizontal visibility to 1000 m or less. These phenomena affect different human activities, mainly those associated with air, maritime, and road transport. Rio Grande city, located in southern Brazil, has one of the main Brazilian ports, and fog occurrences at this location cause several inconveniences, such as the interruption of port activities and increases in operating costs. Thus, a better understanding of fog formation and dissipation, and the consequent improvement in its forecasts, can bring significant help to the port activities in that region. Therefore, this work seeks to evaluate the WRF model’s ability to simulate fog events in Rio Grande city. Four study cases of dense fogs were performed for this goal, as well as a sensitivity test to select the best vertical resolution configuration of the model. Meteorological data from the Rio Grande pilotage station and the Brazilian Coastal Monitoring System buoys were analyzed. Satellite images and synoptic charts were also analyzed for the study cases. The numerical simulations were performed using the WRF model with three nested domains, where 1 km was the highest horizontal resolution. The Fog Stability Index (FSI) and two estimates of horizontal visibility were evaluated. Simulations show promising results, highlighting the ability of the model to identify the fog occurrence in the area of interest and represent aspects of its dissipation process. Furthermore, it is noteworthy that the FSI and the evaluated visibility estimates were sensitive to the occurrence of the events.

Occurrence and characteristics of snowfall on the highest mountain of Mexico (Citlaltépetl volcano) through the ground’s surface temperature

Víctor Soto — 2023-08-01

Snow has great environmental importance. Its physical properties influence the ground temperature; its long-term accumulation adds to the mass of glaciers and is also a clear indicator of climate variability. However, despite the frequency of snowfall in tropical high-mountain environments, its quantitative study is very scarce, and it is non-existent in the case of Mexico. Due to the altitude of a large part of the Mexican territory and the high ecosystem value of the snow, in this work we analyze the temporality, accumulation, and duration of the snow cover on the highest mountain in the country. The data obtained through continuous monitoring of the surface temperature of the ground allowed us to identify that snowfall occurs with greater frequency and volume during the summer and autumn months, while during the winter snowfall of less intensity occurs. The accumulation values are mostly less than 30 cm thick, and the duration of the snowpack is on average less than two weeks; however, there are episodes of greater depth and duration.

Drought Potential in Borneo Based on the RCP 4.5 Scenario

Amalia Nurlatifah — 2023-08-01

One of the impacts of climate change is an increase in the frequency and intensity of hydrometeorological disasters such as prolonged droughts. Borneo is one of the areas threatened by drought due to climate change. Therefore, it is important to identify and implement appropriate mitigation and adaptation measures. This study used the dynamical downscaling method by the Conformal Cubic Atmospheric Model (CCAM) to evaluate the potential for drought events in Borneo based on the RCP 4.5 scenario. The annual rainfall in Borneo for 2021-2050 is projected to increase compared to 1991-2020. However, the increase in annual rainfall does not free Borneo from the possibility of drought events in the future. This study’s results indicate that areas in southern Borneo, such as Banjarmasin, Pangkalan Bun, and Pontianak, will have a higher frequency of meteorological drought events and are also expected to experience longer periods of consecutive dry days between 2021-2050 compared to 1991-2020.

Development and evaluation of a bulk three-moment parameterization scheme incorporating the processes of sedimentation and collision-coalescence

Lainer Donet — 2023-08-01

There are a few three-moment schemes that consider other processes besides sedimentation. Thus, a performance assessment of these types of schemes due to the combined effect of sedimentation and other microphysical processes is a matter of interest. In this study, a warm rain bulk three-moment parameterized scheme was developed and evaluated through a detailed comparison with a bin microphysical scheme. To evaluate the impact of sedimentation and the combined effect of sedimentation and collision-coalescence on the droplet size distribution (DSD), a rain shaft model was applied to the DSD with different initial values of the shape parameter. For pure sedimentation, a good correspondence was obtained between the three-moment scheme and the explicit model, with a practically perfect coincidence of bulk quantities for larger values of the gamma distribution’s initial shape parameter and, in general, the three-moment parameterization scheme performing much better than the two-moment scheme. The simulations performed for this case confirm (as reported in previous studies) that for pure sedimentation, the three-moment parameterization schemes deliver a physically more complete representation of the evolution of droplet size distribution. The impact of the combined effect of sedimentation and collision-coalescence processes on DSD was also assessed. We could observe that certain differences arise between the parameterized scheme and the spectral model when the collision-coalescence process is incorporated, as the onset of precipitation occurs earlier in the three-moment parameterized scheme. It can be concluded that, in general, the three-moment warm rain bulk microphysics scheme is able to reproduce the results of the reference bin microphysical model.