Influence of Atmospheric Aerosol Contamination on the Regional Climate in Central Asia

2006 ◽  
pp. 403-414
Author(s):  
Boris B. Chen ◽  
Valery M. Lelevkin
Keyword(s):  
Central Asia ◽  
Atmospheric Aerosol ◽  
Regional Climate

scholarly journals Variability of the Cold Season Climate in Central Asia. Part I: Weather Types and Their Tropical and Extratropical Drivers

2018 ◽  
Vol 31 (18) ◽  
pp. 7185-7207 ◽  
Author(s):  
Lars Gerlitz ◽  
Eva Steirou ◽  
Christoph Schneider ◽  
Vincent Moron ◽  
Sergiy Vorogushyn ◽  
...  
Keyword(s):  
Central Asia ◽  
Regional Climate ◽  
Cold Season ◽  
Weather Types ◽  
Near Surface ◽  
Climate Conditions ◽  
Temperature Changes ◽  
Central Asian ◽  
Surface Climate ◽  
Moisture Fluxes

To understand the atmospheric mechanisms resulting in a pronounced cold season climate variability in central Asia, an objective weather-type classification is conducted, utilizing a k-means-based clustering approach applied to 500-hPa geopotential height (GPH) fields. Eight weather types (WT) are identified and analyzed with regard to characteristic pressure patterns and moisture fluxes over Eurasia and specific near-surface climate conditions over central Asia. To identify remote drivers of the central Asian climate, WT frequencies are analyzed for their relationships with tropical and extratropical teleconnection modes. The results indicate an influence of Northern Hemispheric planetary wave tracks on westerly moisture fluxes with positive anomalies of precipitation associated with the formation of a Rossby trough over central Asia. Particularly the propagation of the east Atlantic–western Russia and the Scandinavian patterns is shown to modulate regional climate conditions. Variations of ENSO are shown to affect the frequency of particular WTs because of the formation of an anticyclonic anomaly over the Indian Ocean and an increase of tropical fluxes of moisture and heat into central Asia during El Niño events. Further a WT internal influence of ENSO is distinctly defined, with enhanced moisture supply during the ENSO warm phase. The analysis of climatic trends shows that 50% of observed temperature changes can be assigned to variations of the WT composition, indicating that most likely changing regional circulation characteristics account for the enhanced warming rates in central Asia. Trends of precipitation sums are likewise shown to be associated with changing WT frequencies, although the WT–precipitation relationships include large uncertainties.

scholarly journals Evaluation of regional climate models ALARO-0 and REMO2015 at 0.22° resolution over the CORDEX Central Asia domain

2021 ◽  
Vol 14 (3) ◽  
pp. 1267-1293
Author(s):  
Sara Top ◽  
Lola Kotova ◽  
Lesley De Cruz ◽  
Svetlana Aniskevich ◽  
Leonid Bobylev ◽  
...  
Keyword(s):  
High Resolution ◽  
Central Asia ◽  
Climate Models ◽  
Regional Climate ◽  
Regional Climate Models ◽  
Horizontal Resolution ◽  
Maximum Temperature ◽  
The Tibetan Plateau ◽  
Climate Information ◽  
Climate Data

Abstract. To allow for climate impact studies on human and natural systems, high-resolution climate information is needed. Over some parts of the world plenty of regional climate simulations have been carried out, while in other regions hardly any high-resolution climate information is available. The CORDEX Central Asia domain is one of these regions, and this article describes the evaluation for two regional climate models (RCMs), REMO and ALARO-0, that were run for the first time at a horizontal resolution of 0.22∘ (25 km) over this region. The output of the ERA-Interim-driven RCMs is compared with different observational datasets over the 1980–2017 period. REMO scores better for temperature, whereas the ALARO-0 model prevails for precipitation. Studying specific subregions provides deeper insight into the strengths and weaknesses of both RCMs over the CAS-CORDEX domain. For example, ALARO-0 has difficulties in simulating the temperature over the northern part of the domain, particularly when snow cover is present, while REMO poorly simulates the annual cycle of precipitation over the Tibetan Plateau. The evaluation of minimum and maximum temperature demonstrates that both models underestimate the daily temperature range. This study aims to evaluate whether REMO and ALARO-0 provide reliable climate information over the CAS-CORDEX domain for impact modeling and environmental assessment applications. Depending on the evaluated season and variable, it is demonstrated that the produced climate data can be used in several subregions, e.g., temperature and precipitation over western Central Asia in autumn. At the same time, a bias adjustment is required for regions where significant biases have been identified.

Impact of Desiccation of Aral Sea on the Regional Climate of Central Asia Using WRF Model

2017 ◽  
Vol 175 (1) ◽  
pp. 465-478 ◽  
Author(s):  
Ashish Sharma ◽  
Huei-Ping Huang ◽  
Peter Zavialov ◽  
Valentina Khan
Keyword(s):  
Central Asia ◽  
Regional Climate ◽  
Wrf Model ◽  
Aral Sea

scholarly journals Comparison of Cenozoic surface uplift and glacial-interglacial cycles on Himalaya-Tibet paleo-climate: Insights from a regional climate model

2017 ◽  
Author(s):  
Heiko Paeth ◽  
Christian Steger ◽  
Jingmin Li ◽  
Sebastian G. Mutz ◽  
Todd A. Ehlers
Keyword(s):  
Tibetan Plateau ◽  
Regional Climate Model ◽  
Central Asia ◽  
Last Glacial Maximum ◽  
Climate Model ◽  
Regional Climate ◽  
The Tibetan Plateau ◽  
Climate Anomalies ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Abstract. Assessing paleo-climatic changes across the Tibetan Plateau and the underlying driving mechanisms provides insights for the natural variability in the Earth's climate system in response to tectonic processes and global climate change. In this study, we use a high-resolution regional climate model to investigate various episodes of distinct climate states over the Tibetan Plateau region during the Cenozoic rise of the Plateau and Quaternary glacial/interglacial cycles. The main objective is to compare climate changes during the Miocene-Pliocene uplift period with climate anomalies during the last glacial maximum and the mid-Holocene optimum, based on a consistent modeling framework. Reduced plateau elevation leads to regionally differentiated patterns of higher temperature and lower precipitation amount on the plateau itself, whereas surrounding regions are subject to colder conditions. In particular, Central Asia receives much more precipitation prior to the uplift, mainly due to a shift of the stationary wave train over Eurasia. Cluster analysis indicates that the continental-desert type climate, which is widespread over Central Asia today, appears with the Tibetan Plateau reaching 50 % of its present-day elevation. The mid-Holocene is characterized by slightly colder temperatures, and the last glacial maximum by considerably colder conditions over most of central and southern Asia. Precipitation anomalies during these episodes are less pronounced and spatially heterogeneous over the Tibetan Plateau. The simulated changes are in good agreement with available paleo-climatic reconstructions from proxy data. The present-day climate classification is only slightly sensitive to the changed boundary conditions in the Quaternary Quaternary. It is shown that in some regions of the Tibetan Plateau the climate anomalies during the Quaternary Quaternary have been as strong as the changes occurring during the uplift period.

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