A. N. Zolotokrylin

Humidification of drylands in European Russia: The present and future

This paper studies the development of dryland humidification in European Russia in the second half of the 20th century to the first third of the 21st century. The growth in humidification of the territory in recent decades of the 20th century is revealed. The tendency of humidification has changed in the early 21st century. The model estimates of the future climate of Russia, which were obtained using an ensemble of 31 global climate models of CMIP5 project for the period of 2011–2030, indicate that the negative trend of the humidification will persist.

Seasonal Variation of Surface Temperature–Modulating Factors in the Sonoran Desert in Northwestern Mexico

The authors explore a new approach to monitoring of desertification that is based on use of results on the relation between albedo and surface temperature for the Sonoran Desert in northwestern Mexico. The criteria of predominance of radiation by using the threshold value of Advanced Very High Resolution Radiometer (AVHRR) and Moderate Resolution Imaging Spectroradiometer (MODIS) normalized difference vegetation index (NDVI) were determined. The radiation mechanism for regulating the temperature of the surface and the definition of threshold values for AVHRR and MODIS NDVI have an objective justification for the energy budget, which is based on the dominance of radiation surface temperature regulation in relationtoevapotranspiration.Changesin the extentofaridregionswith AVHRRNDVIof ,0.08 andMODIS NDVI of ,0.10 can be considered to be a characteristic in the evolution of desertification in the Sonoran Desert region. This is true because, in a certain year, the time span of the period when radiation factor predominates is important for the desertification process.

Dynamics of Summer Moistening and Biophysical Parameters of Arid Pastures in the European Part of Russia in 2000–2014

The dynamics of moistening indices and biophysical parameters (MODIS data) of arid pastures is examined for the southeast of the European part of Russia in five-year periods over 2000–2014. It was found that the dynamics was heterogeneous both in the temporal and spatial dimensions. The maximal moisture decrease was noted in 2005–2009 in dry-steppe and semidesert pastures. During 2010–2014, the moisture levels continued to decrease, though less intensively compared to the previous five-year period. The dynamics of biophysical parameters is determined by changes in moistening and the degradation of pastures due to overgrazing. The period of 2005–2009 was noted for reduced NDVI, deterioration of the vegetation condi-tions (VCI), and the growth of albedo and surface temperature in dry-steppe and partly semidesert pastures. The following period was marked by a shift of maximal changes in biophysical parameters to the Kalmyk Republic and the right-bank of Astrakhan oblast. This resulted in the appearance of preconditions for new anthropogenic desertification in the territory of Kalmyk Republic, which was detected by the desertification indicator.

Diagnosis of the desertification dynamics of arid pastures in Mongolia from observation in key areas and MODIS data

Changes in the state of Mongolian arid ecosystems revealed in long-term field studies have been analyzed in accordance with the developed concept of island-type desertification. Trends have been revealed in the development of climate aridity, drought frequency, and the anthropogenic load on pastures. Indicators of area moistening, anthropogenic desertification islands, and the overgrazing degree of arid pastures have been developed on the basis of satellite MODIS data. It has been shown that the effects of a sharp reduction in the number of livestock because of natural hazards (dzut, drought) are reliably manifested by a decrease in the surface albedo and an increase in the vegetation index. The dynamics of the islands of anthropogenic desertification has been analyzed. The degree of degradation of dry-steppe, desert-steppe, and desert ecosystems has been estimated snowstorms.

Changes in Aridity across Mexico in the Second Half of the Twentieth Century

AbstractSix regions in Mexico, with typical interannual changes in the aridity index, have been defined by the 1951–2001 meteorological dataset. Peak months of rainfall differ within the regions. Most of the land in the Mexican terrain has had a slow aridization since the early 1980s. The decline in the aridity index in the early 1950s and late 1990s was caused by droughts in the area. The distinctive features of the aridization of Mexican dry lands are characterized by steady and extensive droughts during 1948–57, 1960–65, and 1994–2003 in the second half of the twentieth century. During the drought of 1951–57 substantial aridization in most of the dry lands was observed, including the Sierra Madre Occidental, Sierra Madre Oriental, and Mexican Altiplano. Aridization of dry lands during the drought in 1960–65 affected mostly the southern part of the Mexican Altiplano, the Sierra Madre del Sur, and the Yucatan Peninsula. For the drought in the 1990s, one special feature of the aridization was its propagat...

Trends in Livestock Numbers and Spectral Properties of the Pasture Surface: Case Study of the Middle Gobi Aimag of Mongolia

The paper analyzes linear correlations between MODIS parameters, i.e., the albedo, surface temperature, NDVI, and evapotranspiration, and with annual livestock numbers on Mongolian pastures for June–August throughout 2000–2015. The degree of association between the annual livestock density and average spectral properties of pastures were determined at the level of the whole country, region (aimag), and district (sum). Linear trends were assessed in the annual livestock density and spectral properties of the pasture surface within the boundaries of the specified administrative units of Mongolia. The total density and density with consideration for a structure of the livestock population within the stated territories are weakly related to the average spectral parameters of the pasture surfaces for the territories. The exception is Gurvansaikhan district, in which the relationships are significant; an increase in livestock density increases the albedo, decreases NDVI, and eventually reduces the forage reserve. The R2 coefficients of determination reveal insignificant linear trends in albedo, NDVI, and evapotranspiration as opposed to a significant positive trend in livestock density. A cooling trend and decreased precipitation was evident in 2000–2015. In the years of a sharp drop in livestock density (2000 and 2010), the spectral characteristics of pastures exhibit insignificant departures from the trend line, i.e. their sensitivity to a sharp drop in livestock numbers is minimal in the present situation.

Bioclimatic Subhumid Zone of Russian Plains: Droughts, Desertification, and Land Degradation

The boundaries of bioclimatic zones (semi-arid, dry subhumid, and subhumid) on the plains of Russia were determined according to the values 0.35, 0.50, and 0.75 of the aridity index (AI is the ratio between mean annual rainfall and potential evapotranspiration). The potential evapotranspiration was calculated by the Penman formula. The dry subhumid area (dry steppe landscapes) is located between isolines 0.35 < AI < 0.50, while the subhumid area (mainly steppe landscapes on the East European Plain and forest-steppe ones on the West Siberian Plain) is located between 0.50 < AI < 0.75. The subhumid area is characterized by the high frequency of atmospheric and soil-atmospheric droughts in some regions which may be assessed as episodically arid regions. The satellite indicator of land degradation (albedo) shows a significant positive degradation trend in the dry subhumid and semi-arid areas and an unstable positive trend in the subhumid area.

ИЗМЕНЕНИЯ УРОЖАЙНОСТИ ЗЕРНОВЫХ КУЛЬТУР ЕВРОПЕЙСКОЙ РОССИИ, ВЫЗВАННЫЕ КВАЗИДВУХЛЕТНЕЙ ЦИКЛИЧНОСТЬЮ АТМОСФЕРНЫХ ПРОЦЕССОВ

The objective of work is to study the influence of quasi-biennial oscillation of atmospheric processes on precipitation and frequency of the spring-summer drought against the background of the statistics of cyclonic and anticyclonic activity in different phases of the quasi-biennial oscillation and, consequently, on the yield of wheat in the European part of Russia. The area of the study is the grain zone of European Russia including the North Caucasus, Central Chernozem zone, Volga region and Southern Urals. The timeseries of values of speed and direction of zonal wind on an isobaric surface of 30 hPa for the period 1953–2011 was accepted as data characterizing the “classical” quasi-biennial (Data of Free University of Berlin, https://climatedataguide.ucar.edu). Decadic precipitation totals, indices of PDSI and SPI, snow depth in March, the frequency of centers of cyclones during the period of vegetation classified by phases of quasi-biennial. The increase of snow depth in March is revealed, as well as significant increase in precipitation and a reduction in the frequency of severe droughts in May associated with the intensification of cyclonic activity during the Western phase in relation to Eastern on a vast territory: the western region of Central Chernozem zone, Rostov region and Krasnodar krai. As a result of changing agro-climatic conditions depending on the phase of the quasi-biennial in the territory, it is found a significant excess of productivity of spring wheat during the Western phase against the Eastern phase. The yield of winter wheat was less sensitive to the quasi-biennial. The results of the study can be used to adequately address the problem of increasing the sustainability of harvests in Russia (improvement of agrometeorological practice, including prognostic aspects, and agroinsurance).

The statistics of precipitation and droughts during opposite phases of the quasi-biennial oscillation of atmospheric processes and its relation to the yield in the European part of Russia

As a result of the analysis of the data from weather stations and the values of Palmer Drought Severity Index (PDSI), territorial regularities are revealed in the distribution of total ten-day precipitation, frequency of severe atmospheric droughts in May and June, and spring wheat yield in the European part of Russia depending on the phase of the quasi-biennial oscillation of equatorial stratospheric wind (QBO) in 1953–2010. It is demonstrated that the variations can be explained by differences in the statistics of synoptic cyclonic and anticyclonic vortices during different QBO phases. The spatial structure of differences in ten-day precipitation and frequency of severe droughts on the European part of Russia during opposite phases of the QBO agrees with differences in spring wheat yield. The QBO was considered in the modeling of spring wheat yield in the Rostov oblast, and this allowed improvement of prognostic values of yield by 14%. The results of the simulation of spring wheat yield with account of the quasi-biennial oscillation of stratospheric equatorial wind as a predictor with the relative spatiotemporal stability of values can be used for working out new methods for forecasting the crop yield.

Drought and Grain Crop Yields over the East European Plain under Influence of Quasibiennial Oscillation of Global Atmospheric Processes

Monthly precipitation and the 3-month Standardized Precipitation Index (SPI) were used to reveal the patterns of rainfall and severe drought frequency over the East European Plain in the period 1953–2011 in the opposite phases of the quasibiennial oscillation (QBO). Differences of precipitation and severe drought frequency in May and in June in the westward and eastward phases of the QBO phases are explained by circulation variations. The analysis indicates less frequent severe drought events over Ukraine and at the center of the European part of Russia in May in the westward QBO phase due to the intensification of the storm track over the East European Plain. The weather conditions in May and in June in the years of the westward QBO phase were more favorable for the yield. The difference of spring wheat yield in the westward and eastward QBO phase exceeds the same difference of winter wheat yield in the Central Black Earth region and in the south regions. Ukraine and the region to the east of the Sea of Azov are the most vulnerable areas of increased risk of severe drought during the active growing season at the end of the 20th and beginning of the 21st century.