The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform

Lan Cuo - One of the best experts on this subject based on the ideXlab platform.

  • changes in Moisture Flux over the tibetan plateau during 1979 2011 insights from a high resolution simulation
    Journal of Climate, 2015
    Co-Authors: Yanhong Gao, Ruby L Leung, Yongxin Zhang, Lan Cuo
    Abstract:

    AbstractNet precipitation [precipitation minus evapotranspiration (P − E)] changes between 1979 and 2011 from a high-resolution regional climate simulation and its reanalysis forcing are analyzed over the Tibetan Plateau (TP) and compared to the Global Land Data Assimilation System (GLDAS) product. The high-resolution simulation better resolves precipitation changes than its coarse-resolution forcing, which contributes dominantly to the improved P − E change in the regional simulation compared to the global reanalysis. Hence, the former may provide better insights about the drivers of P − E changes. The mechanism behind the P − E changes is explored by decomposing the column integrated Moisture Flux convergence into thermodynamic, dynamic, and transient eddy components. High-resolution climate simulation improves the spatial pattern of P − E changes over the best available global reanalysis. High-resolution climate simulation also facilitates new and substantial findings regarding the role of thermodynami...

  • Changes in Moisture Flux over the Tibetan Plateau during 1979–2011: Insights from a High-Resolution Simulation
    Journal of Climate, 2015
    Co-Authors: Yanhong Gao, Yongxin Zhang, L. Ruby Leung, Lan Cuo
    Abstract:

    Net precipitation [precipitation minus evapotranspiration (P 2 E)] changes between 1979 and 2011 from a high-resolution regional climate simulation and its reanalysis forcing are analyzed over the Tibetan Plateau (TP) and compared to the Global Land Data Assimilation System (GLDAS) product. The high-resolution simulation better resolves precipitation changes than its coarse-resolution forcing, which contributes dominantly to the improvedP 2Echange in the regional simulation compared to the global reanalysis. Hence,the former may provide better insights about the drivers of P 2 E changes. The mechanism behind the P 2 E changes is explored by decomposing the column integrated Moisture Flux convergence into thermodynamic, dynamic, and transient eddy components. High-resolution climate simulation improves the spatial pattern of P 2 E changes over the best available global reanalysis. High-resolution climate simulation also facilitates new and substantial findings regarding the role of thermodynamics and transient eddies in P 2 E changes reflected in observed changes in major river basins fed by runoff from the TP. The analysis reveals the contrasting convergence/divergence changes between the northwestern and southeastern TP and feedback through latent heat release as an important mechanism leading to the mean P 2 E changes in the TP.

  • changes in Moisture Flux over the tibetan plateau during 1979 2011 and possible mechanisms
    Journal of Climate, 2014
    Co-Authors: Yanhong Gao, Lan Cuo, Yongxin Zhang
    Abstract:

    AbstractChanges in Moisture as represented by P − E (precipitation − evapotranspiration) and the possible causes over the Tibetan Plateau (TP) during 1979–2011 are examined based on the Global Land Data Assimilation Systems (GLDAS) ensemble mean runoff and reanalyses. It is found that the TP is getting wetter as a whole but with large spatial variations. The climatologically humid southeastern TP is getting drier while the vast arid and semiarid northwestern TP is getting wetter. The Clausius–Clapeyron relation cannot be used to explain the changes in P − E over the TP.Through decomposing the changes in P − E into three major components—dynamic, thermodynamic, and transient eddy components—it is noted that the dynamic component plays a key role in the changes of P − E over the TP. The thermodynamic component contributes positively over the southern and central TP whereas the transient eddy component tends to reinforce (offset) the dynamic component over the southern and parts of the northern TP (central T...

Farshad Pazhoh - One of the best experts on this subject based on the ideXlab platform.

  • synoptic analysis of sea level pressure patterns and vertically integrated Moisture Flux convergence vimfc during the occurrence of durable and pervasive rainfall in iran
    Dynamics of Atmospheres and Oceans, 2019
    Co-Authors: Mohammad Darand, Farshad Pazhoh
    Abstract:

    Abstract To carry out this research, interpolated data of daily rainfall from Iran’s Asfazari data base during 1/1/1979–31/12/2013 is used. The day along with pervasive rainfall considered a day that at least 50% of Iran’s territory has received more than 1 mm for at least two consecutive days. Based on mentioned thresholds, 224 days selected for statistical analysis. The sea level pressure data, zonal and meridional wind components and specific humidity with spatial resolution of 0.25*0.25 Gaussian degree in spatial domain of 10 °N to 60 °N and 15 °E to 75 °E obtained from the European Center for Medium range Weather Forecasting (ECMWF) ERA-Interim for selected days. Then on the data matrix of sea level pressure, the cluster analysis by Ward linkage method done and 4 sea level pressure patterns with different configuration of synoptic systems were identified. The findings showed that in the sea level, the interaction between southern thermal low pressure systems (Arabia low pressure) with Europe and Siberia cold immigrant high pressure both by individual and integration and anticyclone circulation of Arab sea from the low level of 1000–500 hPa of troposphere have the most role on occurrence of durable and pervasive rainfall of Iran. The most Vertically Integrated Moisture Flux Convergence in the first layer of troposphere (1000–850 hPa) observed in low height regions, in the second layer of troposphere (775–700 hPa) on Zagros Mountains and in third layer of troposphere (600–500 hPa) is seen in mountains leeward of Iran. Also the results showed that the maximum rainfall cores has the most coordination with Vertically Integrated Moisture Flux Convergence (VIMFC) in the second layer of troposphere (775–700 hPa) on the Zagros heights in the southwest of Iran.

  • Vertically integrated Moisture Flux convergence over Iran
    Climate Dynamics, 2019
    Co-Authors: Mohammad Darand, Farshad Pazhoh
    Abstract:

    The purpose of this study is to identify the vertical integrated Moisture Flux convergence (VIMFC) on the atmosphere of Iran. To achieve this goal, the monthly European Center for Medium range Weather Forecasting gridded data was used during the time period from 1979/1 to 2013/12. Initially, the troposphere was divided into three layers, L1 (850–1000 hPa), L2 (700–775 hPa), and L3 (500–600 hPa) based on the specific Moisture amount in the atmosphere. The average long-term rate of VIMFC was plotted for each layers of the troposphere during different months of the year and relationship between VIMFC and precipitation rates was investigated on Iran. On the basis of the time series of the anomalies of the country’s precipitation, the VIMFC’S rates was divided into two periods of 1979–1998 and 1999–2013. To understand the VIMFC shifts in the different layers of the troposphere and its relationship with precipitation, probability distribution function (PDF) for VIMFC and precipitation was calculated. The findings showed that in the warm months, the VIMFC was far more than the cold months of the year and the VIMFC rate in the L1 is also higher than the other layers of the troposphere. Iran’s atmospheric Moisture sources at the L1 are southern seas such as Red Sea, Arabic Sean, and Persian Gulf that is being driven toward Iran by Saudi Arabia Dynamic High Pressure System and Sudan’s Low Pressure System. In the L2, the Saudi Arabia Dynamic High Pressure is the most important atmospheric system that sends the Moisture of the southern seas to Iran. The PDF shifts of Iran’s precipitation shows a very strong coordination with the VIMFC rate in different months of the year. The findings indicated that in the winter months (JFM), along with decreasing VIMFC rates, the country’s precipitation rate also decreased in the second period of 1999–2013.

Yanhong Gao - One of the best experts on this subject based on the ideXlab platform.

  • changes in Moisture Flux over the tibetan plateau during 1979 2011 insights from a high resolution simulation
    Journal of Climate, 2015
    Co-Authors: Yanhong Gao, Ruby L Leung, Yongxin Zhang, Lan Cuo
    Abstract:

    AbstractNet precipitation [precipitation minus evapotranspiration (P − E)] changes between 1979 and 2011 from a high-resolution regional climate simulation and its reanalysis forcing are analyzed over the Tibetan Plateau (TP) and compared to the Global Land Data Assimilation System (GLDAS) product. The high-resolution simulation better resolves precipitation changes than its coarse-resolution forcing, which contributes dominantly to the improved P − E change in the regional simulation compared to the global reanalysis. Hence, the former may provide better insights about the drivers of P − E changes. The mechanism behind the P − E changes is explored by decomposing the column integrated Moisture Flux convergence into thermodynamic, dynamic, and transient eddy components. High-resolution climate simulation improves the spatial pattern of P − E changes over the best available global reanalysis. High-resolution climate simulation also facilitates new and substantial findings regarding the role of thermodynami...

  • Changes in Moisture Flux over the Tibetan Plateau during 1979–2011: Insights from a High-Resolution Simulation
    Journal of Climate, 2015
    Co-Authors: Yanhong Gao, Yongxin Zhang, L. Ruby Leung, Lan Cuo
    Abstract:

    Net precipitation [precipitation minus evapotranspiration (P 2 E)] changes between 1979 and 2011 from a high-resolution regional climate simulation and its reanalysis forcing are analyzed over the Tibetan Plateau (TP) and compared to the Global Land Data Assimilation System (GLDAS) product. The high-resolution simulation better resolves precipitation changes than its coarse-resolution forcing, which contributes dominantly to the improvedP 2Echange in the regional simulation compared to the global reanalysis. Hence,the former may provide better insights about the drivers of P 2 E changes. The mechanism behind the P 2 E changes is explored by decomposing the column integrated Moisture Flux convergence into thermodynamic, dynamic, and transient eddy components. High-resolution climate simulation improves the spatial pattern of P 2 E changes over the best available global reanalysis. High-resolution climate simulation also facilitates new and substantial findings regarding the role of thermodynamics and transient eddies in P 2 E changes reflected in observed changes in major river basins fed by runoff from the TP. The analysis reveals the contrasting convergence/divergence changes between the northwestern and southeastern TP and feedback through latent heat release as an important mechanism leading to the mean P 2 E changes in the TP.

  • changes in Moisture Flux over the tibetan plateau during 1979 2011 and possible mechanisms
    Journal of Climate, 2014
    Co-Authors: Yanhong Gao, Lan Cuo, Yongxin Zhang
    Abstract:

    AbstractChanges in Moisture as represented by P − E (precipitation − evapotranspiration) and the possible causes over the Tibetan Plateau (TP) during 1979–2011 are examined based on the Global Land Data Assimilation Systems (GLDAS) ensemble mean runoff and reanalyses. It is found that the TP is getting wetter as a whole but with large spatial variations. The climatologically humid southeastern TP is getting drier while the vast arid and semiarid northwestern TP is getting wetter. The Clausius–Clapeyron relation cannot be used to explain the changes in P − E over the TP.Through decomposing the changes in P − E into three major components—dynamic, thermodynamic, and transient eddy components—it is noted that the dynamic component plays a key role in the changes of P − E over the TP. The thermodynamic component contributes positively over the southern and central TP whereas the transient eddy component tends to reinforce (offset) the dynamic component over the southern and parts of the northern TP (central T...

Yongxin Zhang - One of the best experts on this subject based on the ideXlab platform.

  • changes in Moisture Flux over the tibetan plateau during 1979 2011 insights from a high resolution simulation
    Journal of Climate, 2015
    Co-Authors: Yanhong Gao, Ruby L Leung, Yongxin Zhang, Lan Cuo
    Abstract:

    AbstractNet precipitation [precipitation minus evapotranspiration (P − E)] changes between 1979 and 2011 from a high-resolution regional climate simulation and its reanalysis forcing are analyzed over the Tibetan Plateau (TP) and compared to the Global Land Data Assimilation System (GLDAS) product. The high-resolution simulation better resolves precipitation changes than its coarse-resolution forcing, which contributes dominantly to the improved P − E change in the regional simulation compared to the global reanalysis. Hence, the former may provide better insights about the drivers of P − E changes. The mechanism behind the P − E changes is explored by decomposing the column integrated Moisture Flux convergence into thermodynamic, dynamic, and transient eddy components. High-resolution climate simulation improves the spatial pattern of P − E changes over the best available global reanalysis. High-resolution climate simulation also facilitates new and substantial findings regarding the role of thermodynami...

  • Changes in Moisture Flux over the Tibetan Plateau during 1979–2011: Insights from a High-Resolution Simulation
    Journal of Climate, 2015
    Co-Authors: Yanhong Gao, Yongxin Zhang, L. Ruby Leung, Lan Cuo
    Abstract:

    Net precipitation [precipitation minus evapotranspiration (P 2 E)] changes between 1979 and 2011 from a high-resolution regional climate simulation and its reanalysis forcing are analyzed over the Tibetan Plateau (TP) and compared to the Global Land Data Assimilation System (GLDAS) product. The high-resolution simulation better resolves precipitation changes than its coarse-resolution forcing, which contributes dominantly to the improvedP 2Echange in the regional simulation compared to the global reanalysis. Hence,the former may provide better insights about the drivers of P 2 E changes. The mechanism behind the P 2 E changes is explored by decomposing the column integrated Moisture Flux convergence into thermodynamic, dynamic, and transient eddy components. High-resolution climate simulation improves the spatial pattern of P 2 E changes over the best available global reanalysis. High-resolution climate simulation also facilitates new and substantial findings regarding the role of thermodynamics and transient eddies in P 2 E changes reflected in observed changes in major river basins fed by runoff from the TP. The analysis reveals the contrasting convergence/divergence changes between the northwestern and southeastern TP and feedback through latent heat release as an important mechanism leading to the mean P 2 E changes in the TP.

  • changes in Moisture Flux over the tibetan plateau during 1979 2011 and possible mechanisms
    Journal of Climate, 2014
    Co-Authors: Yanhong Gao, Lan Cuo, Yongxin Zhang
    Abstract:

    AbstractChanges in Moisture as represented by P − E (precipitation − evapotranspiration) and the possible causes over the Tibetan Plateau (TP) during 1979–2011 are examined based on the Global Land Data Assimilation Systems (GLDAS) ensemble mean runoff and reanalyses. It is found that the TP is getting wetter as a whole but with large spatial variations. The climatologically humid southeastern TP is getting drier while the vast arid and semiarid northwestern TP is getting wetter. The Clausius–Clapeyron relation cannot be used to explain the changes in P − E over the TP.Through decomposing the changes in P − E into three major components—dynamic, thermodynamic, and transient eddy components—it is noted that the dynamic component plays a key role in the changes of P − E over the TP. The thermodynamic component contributes positively over the southern and central TP whereas the transient eddy component tends to reinforce (offset) the dynamic component over the southern and parts of the northern TP (central T...

Remy Roca - One of the best experts on this subject based on the ideXlab platform.

  • Scale decomposition of atmospheric water budget over West Africa during the monsoon 2006 from NCEP/GFS analyses
    Climate Dynamics, 2010
    Co-Authors: Soline Bielli, Remy Roca
    Abstract:

    NCEP/GFS analysis is used to investigate the scale dependence and the interplay between the terms of the atmospheric water budget over West Africa using a dedicated decomposition methodology. The focus is on a 2-month period within the active monsoon period of 2006. Results show that the dominant scales of seasonal mean precipitation and Moisture Flux divergence over West Africa during the monsoon period are large scales (greater than 1,400 km) except over topography, where mean values of small scales (smaller than 900 km) are strong. Correlations between Moisture Flux divergences in monsoon and African Easterly Jet layers and precipitation indicate that precipitation is strongly correlated to Moisture Flux divergence via both large-scale and small-scale processes, but the correlation signal is quite different depending on the region and vertical layer considered. The analysis of the scales associated with the rainfall and the local evaporation over 3 different regions shows that positive correlation exists over the ocean between precipitation and evaporation especially at large scale. Over the continent south of the Sahel, the correlation is negative and driven by large scale. Over the northern part of Sahel, positive correlation is found, only at small scales during the active monsoon period. Lag correlation reveals that the maximum evaporation over the Sahel occurs 1–3 days after the maximum precipitation with maximum contribution from small-scale processes during the first day. This study shows that NCEP/GFS reproduces well the known atmospheric water budget features. It also reveals a new scale dependence of the relative role of each term of the atmospheric water budget. This indicates that such scale decomposition approach is helpful to clarify the functioning of the water cycle embedded in the monsoon system.