The Experts below are selected from a list of 20010 Experts worldwide ranked by ideXlab platform

Bodo Ahrens - One of the best experts on this subject based on the ideXlab platform.

  • analysis of the indian summer monsoon system in the regional climate model cosmo Clm
    Journal of Geophysical Research, 2010
    Co-Authors: Andreas Dobler, Bodo Ahrens
    Abstract:

    [1] The Indian summer monsoon (ISM) influences daily lives and economies in many countries in the South Asian region. This study analyzes the representation of the ISM system in the regional climate model COSMO-Clm. Simulations driven by ERA-40 reanalysis and present-day (1960–2000) data from the global climate model ECHAM5 are investigated. The ability of COSMO-Clm to reproduce the ISM better than the coarser-grid driving models is tested using a set of well-established, complementary monsoon indices: the all-India monsoon rainfall, vertical wind shear indices, and an outgoing longwave radiation (OLR) index. The results show that regarding these large-scale indices the COSMO-Clm simulations are not more accurate than the driving models. Considering the spatial distribution of rainfall, the ERA-40–driven COSMO-Clm simulations show major overestimations (about 100%) for the west coast of India and underestimations (about 50%) for the Himalayan foothills. Large biases occur in the OLR data over the Arabian Sea and the Bay of Bengal where COSMO-Clm shows high convective activity (OLR < 180 W m−2) at about 3 times as many days as observed in the monsoon season. In the ECHAM5-driven simulation, underestimations of rainfall also appear at the Himalayan foothills. Nevertheless, the application of COSMO-Clm to ECHAM5 improves the temporal correlations of the modeled ISM indices, and the spatial patterns are better simulated in COSMO-Clm with 0.44° horizontal grid spacing than in the large-scale ECHAM5 data.

  • Analysis of the Indian summer monsoon system in the regional climate model COSMO‐Clm
    Journal of Geophysical Research, 2010
    Co-Authors: Andreas Dobler, Bodo Ahrens
    Abstract:

    [1] The Indian summer monsoon (ISM) influences daily lives and economies in many countries in the South Asian region. This study analyzes the representation of the ISM system in the regional climate model COSMO-Clm. Simulations driven by ERA-40 reanalysis and present-day (1960–2000) data from the global climate model ECHAM5 are investigated. The ability of COSMO-Clm to reproduce the ISM better than the coarser-grid driving models is tested using a set of well-established, complementary monsoon indices: the all-India monsoon rainfall, vertical wind shear indices, and an outgoing longwave radiation (OLR) index. The results show that regarding these large-scale indices the COSMO-Clm simulations are not more accurate than the driving models. Considering the spatial distribution of rainfall, the ERA-40–driven COSMO-Clm simulations show major overestimations (about 100%) for the west coast of India and underestimations (about 50%) for the Himalayan foothills. Large biases occur in the OLR data over the Arabian Sea and the Bay of Bengal where COSMO-Clm shows high convective activity (OLR < 180 W m−2) at about 3 times as many days as observed in the monsoon season. In the ECHAM5-driven simulation, underestimations of rainfall also appear at the Himalayan foothills. Nevertheless, the application of COSMO-Clm to ECHAM5 improves the temporal correlations of the modeled ISM indices, and the spatial patterns are better simulated in COSMO-Clm with 0.44° horizontal grid spacing than in the large-scale ECHAM5 data.

Harald Kunstmann - One of the best experts on this subject based on the ideXlab platform.

  • evaluation of the cosmo Clm high resolution climate simulations over west africa
    Journal of Geophysical Research, 2017
    Co-Authors: Diarra Dieng, Gerhard Smiatek, Jan Bliefernicht, Dominikus Heinzeller, A Sarr, Amadou Thierno Gaye, Harald Kunstmann
    Abstract:

    The evaluation of a high-resolution simulation at 0.11∘(12km) with the COSMO-Clm (CClm) regional climate model, applied over West Africa, is presented. This simulation is nested in a CClm run at resolution of 0.44∘, driven with boundary forcing data from the ERA-Interim reanalysis, and covers the period from 1981 to 2010. The simulated temperature and precipitation are evaluated using three selected climate indices for temperature and eight indices for precipitation in five different regions against a new, daily precipitation climatology covering West Africa and against other state of the art climatologies. The obtained results indicate that CClm is able to reproduce the observed major climate characteristics including the West African Monsoon within the range of comparable RCM evaluations studies, but substantial uncertainties remain, especially in the Sahel zone. The seasonal mean temperature bias for the rainy season from June to September ranges from -0.8 ∘ C to -1.1 ∘ C. The CClm simulations also underestimate the observed precipitation with biases in precipitation reaching -10% in the high-resolution and -20% in the low-resolution model runs. CClm extends the monsoon precipitation belt too far north, which results in an overestimation of precipitation in the Sahel zone of up to 60%. In the coastal zone, the precipitation is underestimated by up to -90%. These biases in precipitation amounts are associated with errors in the precipitation seasonality. The added value of the higher resolution of the nested run is reflected in a smaller bias in extreme precipitation statistics with respect to the reference data.

Steven Cocke - One of the best experts on this subject based on the ideXlab platform.

  • evaluation of soil moisture in the florida state university climate model national center for atmospheric research community land model fsu Clm using two reanalyses r2 and era40 and in situ observations
    Journal of Geophysical Research, 2006
    Co-Authors: M Boisserie, D W Shin, T E Larow, Steven Cocke
    Abstract:

    [1] The simulated soil moisture from the Florida State University (FSU) climate model coupled to the National Center for Atmospheric Research community land model (Clm2) is evaluated using two reanalyses (the European Centre for Medium-Range Weather Forecasts 40-year Reanalysis (ERA40) and the National Centers for Environmental Prediction/Department of Energy Reanalysis 2 (R2)) and in situ observations in Illinois and China from the Global Soil Moisture Data Bank. While the soil moisture was prescribed in the previous FSU climate model, the implementation of the Clm2 within the FSU model (hereafter FSU-Clm) provides a prognostic soil moisture (both soil liquid water and soil ice) in 10 vertical layers. For the first layer (∼0–10 cm) the comparison of the soil moisture annual cycle between the FSU-Clm and the two reanalyses shows that in the Northern Hemisphere (NH) the FSU-Clm and the ERA40 are in phase but they are out of phase with the R2. While a parameterization of the soil ice process is included in both the FSU-Clm and ERA40, it is not included in the R2. In this study, we found that the soil ice plays a key role in determining the soil moisture variation over the NH. The two reanalyses and the FSU-Clm are also compared with in situ observations. The FSU-Clm turns out to follow the annual cycle of the in situ observations better than both reanalyses.

Andreas Dobler - One of the best experts on this subject based on the ideXlab platform.

  • analysis of the indian summer monsoon system in the regional climate model cosmo Clm
    Journal of Geophysical Research, 2010
    Co-Authors: Andreas Dobler, Bodo Ahrens
    Abstract:

    [1] The Indian summer monsoon (ISM) influences daily lives and economies in many countries in the South Asian region. This study analyzes the representation of the ISM system in the regional climate model COSMO-Clm. Simulations driven by ERA-40 reanalysis and present-day (1960–2000) data from the global climate model ECHAM5 are investigated. The ability of COSMO-Clm to reproduce the ISM better than the coarser-grid driving models is tested using a set of well-established, complementary monsoon indices: the all-India monsoon rainfall, vertical wind shear indices, and an outgoing longwave radiation (OLR) index. The results show that regarding these large-scale indices the COSMO-Clm simulations are not more accurate than the driving models. Considering the spatial distribution of rainfall, the ERA-40–driven COSMO-Clm simulations show major overestimations (about 100%) for the west coast of India and underestimations (about 50%) for the Himalayan foothills. Large biases occur in the OLR data over the Arabian Sea and the Bay of Bengal where COSMO-Clm shows high convective activity (OLR < 180 W m−2) at about 3 times as many days as observed in the monsoon season. In the ECHAM5-driven simulation, underestimations of rainfall also appear at the Himalayan foothills. Nevertheless, the application of COSMO-Clm to ECHAM5 improves the temporal correlations of the modeled ISM indices, and the spatial patterns are better simulated in COSMO-Clm with 0.44° horizontal grid spacing than in the large-scale ECHAM5 data.

  • Analysis of the Indian summer monsoon system in the regional climate model COSMO‐Clm
    Journal of Geophysical Research, 2010
    Co-Authors: Andreas Dobler, Bodo Ahrens
    Abstract:

    [1] The Indian summer monsoon (ISM) influences daily lives and economies in many countries in the South Asian region. This study analyzes the representation of the ISM system in the regional climate model COSMO-Clm. Simulations driven by ERA-40 reanalysis and present-day (1960–2000) data from the global climate model ECHAM5 are investigated. The ability of COSMO-Clm to reproduce the ISM better than the coarser-grid driving models is tested using a set of well-established, complementary monsoon indices: the all-India monsoon rainfall, vertical wind shear indices, and an outgoing longwave radiation (OLR) index. The results show that regarding these large-scale indices the COSMO-Clm simulations are not more accurate than the driving models. Considering the spatial distribution of rainfall, the ERA-40–driven COSMO-Clm simulations show major overestimations (about 100%) for the west coast of India and underestimations (about 50%) for the Himalayan foothills. Large biases occur in the OLR data over the Arabian Sea and the Bay of Bengal where COSMO-Clm shows high convective activity (OLR < 180 W m−2) at about 3 times as many days as observed in the monsoon season. In the ECHAM5-driven simulation, underestimations of rainfall also appear at the Himalayan foothills. Nevertheless, the application of COSMO-Clm to ECHAM5 improves the temporal correlations of the modeled ISM indices, and the spatial patterns are better simulated in COSMO-Clm with 0.44° horizontal grid spacing than in the large-scale ECHAM5 data.

Liu Wei - One of the best experts on this subject based on the ideXlab platform.

  • INFLUENCES OF PRETREATMENT ON Zn/Al-Clm CATALYST FOR PROPANE AROMATIZATION
    Journal of Fuel Chemistry and Technology, 2002
    Co-Authors: Liu Wei
    Abstract:

    The influences of different pretreatment of Zn/Al Clm catalysts on propane aromatization were carried out with a pulse flow fix bed reactor system The results show that the Zn/Al Clm catalyst show some activity of propane aromatization and can selectively convert propane to benzene The calcination temperature of Al Clm, Zn loading and activation temperature of Zn/Al Clm made much influence on propane aromatization Zn/Al Clm has the best structure and show the best armatization property when Al Clm was calcinated at 500?℃ for 2?h The more the Zn loading, the higher the propane conversion, and aromatics selectivity is the best with loading of 5 8% Zn The effect between Zn and Al Clm was well situated with activation treatment of Zn/Al Clm at 400?℃ in air flow for 2?h, and the yield of aromatics was the highest

  • THE DISPERSITY OF MOLYBDENUM ON THE SURFACE OF Mo/Al-Clm AND ITS HYDRODESULFURIZATION ACTIVITY
    2000
    Co-Authors: Liu Wei
    Abstract:

    The dispersity of MoO 3 or APM on the surface of Mo/Al Clm was determined by X ray diffraction(XRD) The results showed that the XRD peaks of MoO 3 or APM crystalline disappeard if the Mo loading was low in the Mo/Al Clm catalysts which were prepared either by impregration or mixed heating method The XRD peaks of Mo species were observed when the Mo loadings were high The Mo/Al Clm catalysts of medium leveled Mo content showed the highest activity of hydrodesulfurization The monolayer dispersed Mo which isnt extracted by ammonia is the HDS active site Ammonia can extract Mo crystalline and a portion of non active dispersed Mo Then the active Mo species on the surface of Mo/Al Clm can be exposed to the reactants and the activity of Mo/Al Clm was thus improved