Atmósfera (Journal)
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Management and ensemble of future climate scenarios for specific agricultural systems in the municipality of Nilo, Cundinamarca (Colombia)
Get PDFThis study proposes a method for averaging future climate scenarios from multiple global models through a multivariate statistical analysis. The method gives more weight to the most relevant variables in a specific system, which is associated with the availability of water resources. The proposal considered a climate baseline (precipitation, temperature, relative humidity, wind speed, sunlight) registered in stations near the municipality of Nilo, Colombia (illustrated as a case study), and the future climate scenarios derived from 11 models and 4 scenarios of greenhouse gas emissions (representative concentration pathways, RCPs). Additionally, other variables derived from the current and future water balances (WB) were taken into consideration, such as: deficit (Def), potential evapotranspiration (ETo), real evapotranspiration (ETR), excess (Exc), and other indexes which determine the aridity of a region such as the Lang’s index (IL) and the hydric availability index (HAI). Results suggest that by 2070, precipitation may decrease by 14.0% in the arithmetic average and 25.3% in the weighted average with respect to the current condition (1292 mm yr–1), decreasing to 1111.5 and 964.8 mm, respectively. Additionally, the arithmetic average projects an increase of 2.3 ºC in the average temperature, while the weighted average projects an increase of 2.7 ºC. The proposed methodology is a useful tool to analyze multiple climate change scenarios
Emission impact of wildfires: El Tepozteco 2016
Get PDFWildfires impact both ecosystems and human welfare, being carbon monoxide and PM2.5 particles the most critical emissions affecting human health. The impact of a fire in the Tepozteco National Park, in the state of Morelos, Mexico was evaluated on its potential to produce health impacts on the surrounding inhabitants. Surrounding population centers are located at around 2000 m from the area affected by the wildfire, which occurred in a natural protected natural area. HYSPLIT simulations to estimate pollutant trajectories were conducted along with a dispersion simulation to determine pollutant concentrations as a function of distance to the centers of population. The results show that the inhabitants of adjacent communities were not subject to significant risk levels according to national and international regulations, because the dispersion trajectory of the pollutants did not impact such populations. In Mexico, it is necessary to prioritize prevention, monitoring, and mitigation measures of human-induced wildfires. It is recommended to increase the coverage of the monitoring network of Morelos to include the Tepoztlán Municipality, due to the high frequency of fires and the growing urbanization in the zone
Ozone variation during a case of cyclogenesis
Get PDFThe relationship between total column ozone (TCO) and the development of a cyclonic system that occurred in the period from January 18 to January 25, 1981 has been studied using the ERA-Interim reanalysis database. It was found that TCO increases and decreases with the development and weakening of the cyclonic system. Also, a good correlation between TCO and the thickness of the layer was found between 1000-100 hPa and tropopause pressure. The study of daily variations in TCO based on the vertical distribution of the ozone mass mixing ratio (OMR) illustrate that with the beginning of the growth period there is a high decrease of the tropopause height, which was associated to high deepening of the cyclone and was accompanied by a significant vertical increase of OMR in the troposphere and stratosphere. The obvious significant increase of OMR starts at the stratospheric layer and is then transported to the tropospheric layer. The analysis of the time-height variation of the differences of OMR between the average of the domain containing the center of the cyclone at each level and the corresponding monthly average, illustrates that during the days of maximum deepening the positive values of OMR extend downwards to reach the 850 hPa level. The increase in positive values continues to be higher in the upper levels and reaches maximum values between 300-100 hPa and also between the 60-10 hPa layer. The characteristics of these changes of OMR concentrations from layer to layer are predominantly due to dynamical processes. Also, this was attributed to the effect of horizontal advection of ozone from a different neighboring region into the column, and by a vertical exchange of air between the high ozone at the stratosphere and low ozone at troposphere
Long-term observation of black carbon aerosols at an urban location over the central Indo-Gangetic Plain, South Asia
Get PDFThe first ever long-term measurement of black carbon (BC) aerosols over an urban location at the central Indo-Gangetic Plain (IGP) is presented. Both short- and long-term variations in BC during the period 2009-2013 are discussed with specific emphasis on variation in BC sources, meteorology, trend and possible transport pathways across the IGP. High BC mass loading was noted with a 5-yr composite mean (± SD) of 11.8 (± 8.6) µg m–3, having strong and consistent seasonal variations (median: 8.8; range: 1.4-48.0 µg m–3). Winter (21.5 ± 9.9µ gm–3) and post-monsoon (17.4 ± 10.2 µg m–3) specific rises in BC mass were consistent with the increase in household emissions, and from agricultural residue burning. The BC mass concentration was mostly influenced by local sources, while sudden change in BC was consistent with the change in Delta-C, indicating emissions primarily from biomass burning. Beside sources, atmospheric boundary layer height was noted to considerably influence short-term variations in BC concentration. A statistically significant monotonic increasing trend in BC concentration (0.9 µg m–3 yr–1) was computed along with its 95% uncertainty bounds (0.38-1.52 µ gm–3 yr–1). Increase in BC concentration was consistent with a rise in BC sources across the IGP and over India. Furthermore, clear evidence of local and regional scale transport of BC aerosols was found using the particle Lagrangian model
Synergy between INSAT-3D infra-red and GPM microwave radiometer for precipitation studies
Get PDFThe Indian National Satellite System (INSAT) based Multispectral Rainfall Algorithm (IMSRA) operationally provides precipitation estimates using measurements provided by the Kalpana satellite from 2008 onwards and the INSAT-3D from 2014 onwards over Indian land and oceanic regions for dissemination to the users. Here, an attempt is made to estimate rainfall over the Indian monsoon region by the synergistic use of geostationary INSAT-3D IMSRA derived rainfall estimates and rain data from the Global Precipitation Measurement (GPM) Microwave Imager (GMI) using a suitable objective analysis method. The objective criteria of a successive correction method benefit from high spatial and temporal resolutions of the geostationary satellite and infrequent but more accurate microwave-based rainfall estimates, particularly during heavy rain conditions. The method is applied to various case studies for the southwest monsoon season of 2015 at both instantaneous and daily scale. A comparison is made with ground data and also with independent global concurrent rainfall products. The merged rainfall estimates shows noticeable improvement over the Infrared (IR)-based rainfall estimates over various parts of the Indian land and oceanic regions on a daily scale. Overall, results reveal that the GMI type radiometer in low inclination orbit like the Megha-Tropiques and Tropical Rainfall Measurement Mission (TRMM) could be more useful for synergistic use with INSAT-3D. It has the potential to predict more accurately near real-time tropical rainfall, particularly over the Indian monsoon region, which makes it a valuable source of information for flood forecasting, agriculture and water resource management, numerical weather prediction, and numerous other applications in the hydro-meteorological sciences
Influence evaluation of PM10 produced by the burning of biomass in Peru on AOD, using the WRF-Chem
Get PDFThis study assesses the influence of PM10 on the optical thickness of aerosols in the central Andes of Peru, in addition to analyzing and establishing their circulation patterns from July to October 2017. This particular period is considered herein because the largest biomass burning events are usually recorded during these months. The regional meteorological-chemistry transport model WRF-Chem (version 3.7) was used with the Fire Inventory from NCAR (FINN) fire emissions dataset and aerosol optical depth (AOD) data from the Aerosol Robotic Network monitoring network (AERONET), which has a CIMEL sun photometer located at the Huancayo Observatory, the most important city in the central highlands of Peru. The simulation used a single domain with a grid size of 18 km and 32 vertical levels. Results showed an increase in PM10 concentrations with an increase in the number of fire outbreaks and AOD during July, August, and September. In contrast, a slight decrease in PM10 concentrations was recorded for October. Further, the meteorological conditions did not favor the occurrence of fire outbreaks in the Mantaro valley during the entire study period; however, an increase in rainfall reduced aerosol concentrations in October. In addition, although the vertical movements prevailing over the central Andes were ascending, they were descending along the Peruvian coast, thus favoring and hindering the dispersion of aerosols in the first and second cases, respectively. Finally, the authors assessed, analyzed, and confirmed the influence of biomass burning on AOD in the studied region
Partitioning of the water soluble versus insoluble fraction of trace elements in the city of Santiago, Chile
Get PDFThe total elemental composition and the water-soluble fraction of PM10 from three different urban areas in Santiago, Chile, from downtown to the suburbs, were investigated. PM10 samples collected during the month of May (mid-autumn in the Southern Hemisphere) in 2006, 2008, 2009, and 2010 were analyzed for major and trace metals, and the partitioning between the insoluble and soluble fractions was determined for most of them. PM10 average concentrations ranged from 71 µg m–3 (Cerrillos) to 128 µg m–3 (La Pintana), which are within the seasonal ranges observed in Santiago. Twenty five major and trace elements (Fe, Al, Ca, K, Mg, P, Pb, S, Ti, Mn, Cu, Zn, Ba, Zr, Cr, As, Sn, Sb, Ni, V, Li, Co, Cd, La, and Rb) were determined in the present study. Ba, Sb, Cd, As, and Zn, with proportions in the soluble fraction varying from 50% to 98%, were the most soluble elements. On the contrary, the less soluble trace elements were Ti, Sn, Pb, and Cr. Most of the high-solubility trace metals are strongly linked to non-exhaust traffic emissions, as well as to certain industrial sources. Our results evidence the significant amount of soluble trace elements in Santiago’s urban atmosphere classified as toxic and/or carcinogenic, thus suggesting a non-negligible health impact
A novel velocity dealiasing algorithm for S-Band weather radars
Get PDFNoise, especially continuous noise, is an important factor that affects the velocity dealiasing of Doppler weather radars. A challenge in the design of dealiasing algorithm is how to effectively suppress noise. Therefore, a novel anti-noise dealiasing algorithm (AND) for Doppler velocities was proposed in this paper. In comparison with traditional methods, the AND utilizes a new separation-restoration noise suppression scheme, which can significantly reduce the interference of noise on dealiasing without losing data. This algorithm utilizes three fitting curves as references to correct ambiguous echoes, and it can further suppress residual noise and dynamically match wind fields at varying scales. The AND has been applied to the CINRAD-SA network of operational radars in China, achieving a better performance on noisy echoes, isolated echoes, typhoon echoes, and tornado echoes
Spatial and temporal Hurst exponent variability of rainfall series based on the climatological distribution in a semiarid region in Mexico
Get PDFA fractal analysis from rainfall events registered in a semiarid region was carried out. The analysis was executed for Baja California, Mexico, a region that presents a high climatological variability. Rainfall data from 92 climate stations distributed along the region of study with at least 30 years of records were used. By studying the rainfall series patterns, the Hurst exponent values were obtained (both spatial and temporal) as well as their relation with the variables for annual average temperature, annual average rainfall, altitude and climatological distribution. The rescaled range method, box counting method, and multifractal detrended fluctuation analysis were successfully applied, having as a result the average value of the Hurst exponent for different time scales. Data showed that the daily rainfall series tend to present a persistent pattern; besides, the Hurst exponent values (Hu) were related to the type of climate, altitude, rainfall regime, and temperature of the studied area. The analysis of the Hurst exponent for different time scales showed that, at a smaller time scale, the Hurst value tends to increase; thus, the series present a stronger persistent behavior. Moreover, it can be confirmed that the fractal theory methodology allows analyzing the behaivor of a climate variable, in this case rainfall
Seasonal rainfall variability in the southern Mediterranean border: Observations, regional model simulations and future climate projections
Get PDFParticular attention has been given in recent years to precipitation and variations in climate change scenarios by modeling these phenomena at different timescales. Regional climate models enable assessing the impact of climate change at the regional and local scales. This study aims, firstly, to analyze the rainfall variability in northern Algeria, and secondly, to evaluate future seasonal rainfall variability using regional climate models of the ENSEMBLE project. A statistical test and the bias method have been used for this study. Analysis of rainfall variability using the Pettitt test during the reference period (1961-1990) reveals a significant decrease of rainfall since the 1970s at the Tenes and Oran stations, located in the northwest of Algeria. This decrease occurs during the months of December and January (in winter), and March and April (in spring), and is associated to a reduction of 10-20 and 20-50 mm of daily rainfall, respectively, while the rainfall increases in the eastern region. Simulated data of 12 regional climate models have been compared to observations carried out during the reference period (1961-1990) using the bias method. Future seasonal rainfall variability was analyzed for two projection periods: 2021-2050 and 2070-2099. Most often, models underestimate the wet seasons and overestimate the dry seasons during the reference period. The models simulated a significant decrease of future rainfall in winter and spring over the two projected periods. Further investigations must be conducted to explain the underestimation of the models. It is also important to reconsider uncertainties that affect the results of this study