Impact of Atmospheric Surface-layer Parameterizations in the new Land-surface Scheme of the NCEP Mesoscale Eta Model

1997 ◽  
Vol 85 (3) ◽  
pp. 391-421 ◽  
Author(s):  
Fei Chen ◽  
Zavisă Janjić ◽  
Kenneth Mitchell
Keyword(s):  
Surface Layer ◽  
Land Surface ◽  
Atmospheric Surface Layer ◽  
Land Surface Scheme ◽  
Eta Model ◽  
Surface Scheme

scholarly journals Soil Surface Energy and Water Budgets during a Monsoon Season in Korea

2009 ◽  
Vol 10 (6) ◽  
pp. 1379-1396 ◽  
Author(s):  
Claudio Cassardo ◽  
Seon Ki Park ◽  
Bindu Malla Thakuri ◽  
Daniela Priolo ◽  
Ying Zhang
Keyword(s):  
Heat Flux ◽  
Surface Layer ◽  
Latent Heat ◽  
Land Surface ◽  
Process Model ◽  
Large Scale ◽  
Sensible Heat Flux ◽  
Land Surface Scheme ◽  
Soil Temperatures ◽  
Surface Scheme

Abstract In this study, attention has been focused on the climatology of some variables linked to the turbulent exchanges of heat and water vapor in the surface layer during a summer monsoon in Korea. In particular, the turbulent fluxes of sensible and latent heat, the hydrologic budget, and the soil temperatures and moistures have been analyzed. At large scale, because the measurements of those data are not only fragmentary and exiguously available but also infeasible for the execution of climatologic analyses, the outputs of a land surface scheme have been used as surrogate of observations to analyze surface layer processes [this idea is based on the methodology Climatology of Parameters at the Surface (CLIPS)] in the Korean monsoonal climate. Analyses have been made for the summer of 2005. As a land surface scheme, the land surface process model (LSPM) developed at the University of Torino, Italy, has been employed, along with the data collected from 635 Korean meteorological stations. The LSPM predictions showed good agreement with selected observations of soil temperature. Major results show that, during the rainfall season, soil moisture in the first tenths of centimeters frequently exceeds the field capacity, whereas most of the rainfall is “lost” as surface runoff. Evapotranspiration is the dominant component of the energy budget, sometimes even exceeding net radiation, especially during the short periods between the precipitation events; in these periods, daily mean soil temperatures are about 28°C or even more. The Gyeonggi-do region, the metropolitan area surrounding Seoul, shows some particularities when compared with the neighboring regions: solar radiation and precipitations are lower, causing high values of sensible heat flux and soil temperatures, and lower values of latent heat flux and soil moistures.

scholarly journals Interactive coupling of regional atmosphere with biosphere in the new generation regional climate system model REMO-iMOVE

2014 ◽  
Vol 7 (3) ◽  
pp. 1093-1114 ◽  
Author(s):  
C. Wilhelm ◽  
D. Rechid ◽  
D. Jacob
Keyword(s):  
Land Surface ◽  
Regional Climate ◽  
Regional Model ◽  
Horizontal Resolution ◽  
Soil Conditions ◽  
Data Sets ◽  
Vegetation Phenology ◽  
Land Surface Scheme ◽  
New Model ◽  
Surface Scheme

Abstract. The main objective of this study is the coupling of the regional climate model REMO with a new land surface scheme including dynamic vegetation phenology, and the evaluation of the new model version called REMO with interactive MOsaic-based VEgetation: REMO-iMOVE. First, we focus on the documentation of the technical aspects of the new model constituents and the coupling mechanism. The representation of vegetation in iMOVE is based on plant functional types (PFTs). Their geographical distribution is prescribed to the model which can be derived from different land surface data sets. Here, the PFT distribution is derived from the GLOBCOVER 2000 data set which is available on 1 km × 1 km horizontal resolution. Plant physiological processes like photosynthesis, respiration and transpiration are incorporated into the model. The vegetation modules are fully coupled to atmosphere and soil. In this way, plant physiological activity is directly driven by atmospheric and soil conditions at the model time step (two minutes to some seconds). In turn, the vegetation processes and properties influence the exchange of substances, energy and momentum between land and atmosphere. With the new coupled regional model system, dynamic feedbacks between vegetation, soil and atmosphere are represented at regional to local scale. In the evaluation part, we compare simulation results of REMO-iMOVE and of the reference version REMO2009 to multiple observation data sets of temperature, precipitation, latent heat flux, leaf area index and net primary production, in order to investigate the sensitivity of the regional model to the new land surface scheme and to evaluate the performance of both model versions. Simulations for the regional model domain Europe on a horizontal resolution of 0.44° had been carried out for the time period 1995–2005, forced with ECMWF ERA-Interim reanalyses data as lateral boundary conditions. REMO-iMOVE is able to simulate the European climate with the same quality as the parent model REMO2009. Differences in near-surface climate parameters can be restricted to some regions and are mainly related to the new representation of vegetation phenology. The seasonal and interannual variations in growth and senescence of vegetation are captured by the model. The net primary productivity lies in the range of observed values for most European regions. This study reveals the need for implementing vertical soil water dynamics in order to differentiate the access of plants to water due to different rooting depths. This gets especially important if the model will be used in dynamic vegetation studies.

scholarly journals Sensitivity study of the regional climate model RegCM4 to different convective schemes over West Africa

2018 ◽  
Vol 9 (4) ◽  
pp. 1261-1278 ◽  
Author(s):  
Brahima Koné ◽  
Arona Diedhiou ◽  
N'datchoh Evelyne Touré ◽  
Mouhamadou Bamba Sylla ◽  
Filippo Giorgi ◽  
...  
Keyword(s):  
West Africa ◽  
Land Surface ◽  
West African ◽  
Cold Bias ◽  
The West ◽  
Land Surface Scheme ◽  
African Climate ◽  
Sensitivity Studies ◽  
Surface Scheme ◽  
Convective Scheme

Abstract. The latest version of RegCM4 with CLM4.5 as a land surface scheme was used to assess the performance and sensitivity of the simulated West African climate system to different convection schemes. The sensitivity studies were performed over the West African domain from November 2002 to December 2004 at a spatial resolution of 50 km × 50 km and involved five convective schemes: (i) Emanuel; (ii) Grell; (iii) Emanuel over land and Grell over ocean (Mix1); (iv) Grell over land and Emanuel over ocean (Mix2); and (v) Tiedtke. All simulations were forced with ERA-Interim data. Validation of surface temperature at 2 m and precipitation were conducted using data from the Climate Research Unit (CRU), Global Precipitation Climatology Project (GPCP) and the Tropical Rainfall Measurement Mission (TRMM) during June to September (rainy season), while the simulated atmospheric dynamic was compared to ERA-Interim data. It is worth noting that the few previous similar sensitivity studies conducted in the region were performed using BATS as a land surface scheme and involved less convective schemes. Compared with the previous version of RegCM, RegCM4-CLM also shows a general cold bias over West Africa whatever the convective scheme used. This cold bias is more reduced when using the Emanuel convective scheme. In terms of precipitation, the dominant feature in model simulations is a dry bias that is better reduced when using the Emanuel convective scheme. Considering the good performance with respect to a quantitative evaluation of the temperature and precipitation simulations over the entire West African domain and its subregions, the Emanuel convective scheme is recommended for the study of the West African climate system.

scholarly journals The Effect of Soil and Vegetation Parameters in the ECMWF Land Surface Scheme

2004 ◽  
Vol 5 (6) ◽  
pp. 1131-1146 ◽  
Author(s):  
H. Richter ◽  
A. W. Western ◽  
F. H. S. Chiew
Keyword(s):  
Soil Moisture ◽  
Land Surface ◽  
Weather Prediction ◽  
Lower Boundary ◽  
Soil Parameters ◽  
Model Parameters ◽  
Lower Boundary Condition ◽  
Land Surface Scheme ◽  
Vegetation Parameters ◽  
Surface Scheme

Abstract Numerical Weather Prediction (NWP) and climate models are sensitive to evapotranspiration at the land surface. This sensitivity requires the prediction of realistic surface moisture and heat fluxes by land surface models that provide the lower boundary condition for the atmospheric models. This paper compares simulations of a stand-alone version of the European Centre for Medium-Range Weather Forecasts (ECMWF) land surface scheme, or the Viterbo and Beljaars scheme (VB95), with various soil and vegetation parameter sets against soil moisture observations across the Murrumbidgee River catchment in southeast Australia. The study is, in part, motivated by the adoption of VB95 as the operational land surface scheme by the Australian Bureau of Meteorology in 1999. VB95 can model the temporal fluctuations in soil moisture, and therefore the moisture fluxes, fairly realistically. The monthly model latent heat flux is also fairly insensitive to soil or vegetation parameters. The VB95 soil moisture is sensitive to the soil and, to a lesser degree, the vegetation parameters. The model exhibits a significant (generally wet) bias in the absolute soil moisture that varies spatially. The use of the best Australia-wide available soils and vegetation information did not improve VB95 simulations consistently, compared with the original model parameters. Comparisons of model and observed soil moistures revealed that more realistic soil parameters are needed to reduce the model soil moisture bias. Given currently available continent-wide soils parameters, any initialization of soil moisture with observed values would likely result in significant flux errors. The soil moisture bias could be largely eliminated by using soil parameters that were derived directly from the actual soil moisture observations. Such parameters, however, are only available at very few point locations.

scholarly journals Sensitivity tests of the Canadian Land Surface Scheme (CLASS) for Arctic tundra

1997 ◽  
Vol 25 ◽  
pp. 46-50 ◽  
Author(s):  
Jeffrey S. Tilley ◽  
William L. Chapman ◽  
Wanli Wu
Keyword(s):  
Land Surface ◽  
Initial Conditions ◽  
Soil Depth ◽  
Arctic Tundra ◽  
Systems Science ◽  
Initial Water ◽  
Land Surface Scheme ◽  
Internal Parameters ◽  
Canadian Land Surface Scheme ◽  
Surface Scheme

We have conducted tests of the Canadian Land Surface Scheme (CLASS V2.5) for Arctic tundra applications. Our tests emphasize sensitivities to initial conditions, external forcings and internal parameters, and focus on the Alaskan North Slope during the summer of 1992. Observational data from the National Science foundation (NSF), Arctic Systems Science (ARCSS), Land/Atmosphere/Ice Interactions (LAII) Flux Study is available to serve as forcing and validation for our simulations.Comparisons of the runs show strong sensitivities to the composition and depth of the soil layers, and we find that a minimum total soil depth of 5.0 m is needed to maintain permafrost. The response of the soil to diurnal variations in forcing is strong, while sensitivities to other internal parameters, as well as to precipitation, were relatively small. Some sensitivity to air temperatures and radiative fluxes, particularly the incoming shortwave flux, was also present. Significant sensitivity to the specification of the initial water and ice contents of the soil was found, while the sensitivity to initial soil temperature was somewhat less.

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