scholarly journals Evaluation of the ground heat flux simulated by a multi-layer land surface scheme using high-quality observations at grass land and bare soil

2016 ◽  
Vol 25 (5) ◽  
pp. 607-620 ◽  
Author(s):  
Jan-Peter Schulz ◽  
Gerd Vogel ◽  
Claudia Becker ◽  
Steffen Kothe ◽  
Udo Rummel ◽  
...  
Keyword(s):  
Heat Flux ◽  
Land Surface ◽  
Bare Soil ◽  
High Quality ◽  
Land Surface Scheme ◽  
Grass Land ◽  
Ground Heat Flux ◽  
Surface Scheme

scholarly journals Multi-objective calibration of the land surface scheme TERRA/LM using LITFASS-2003 data

2005 ◽  
Vol 9 (6) ◽  
pp. 586-596 ◽  
Author(s):  
K.-P. Johnsen ◽  
H.-T. Mengelkamp ◽  
S. Huneke
Keyword(s):  
Heat Flux ◽  
Latent Heat ◽  
Land Surface ◽  
Vegetation Type ◽  
Sensible Heat Flux ◽  
Heat Fluxes ◽  
Land Surface Scheme ◽  
Multi Objective ◽  
Long Term Study ◽  
Surface Scheme

Abstract. The turbulent sensible and latent heat fluxes simulated in the operational weather forecast model LM have been checked with data from the field experiment LITFASS 2003 (Lindenberg Inhomogeneous Terrain - Fluxes between Atmosphere and Surface: a Long-term Study) using both single site measurements and grid box aggregated fluxes. SCE-UA (single objective) and MOSCEM-UA (multi-objective) approaches were applied to calibrate the land-surface scheme TERRA/LM for 11 single sites and for the aggregated fluxes. A large variation is seen among the parameter sets found by calibration but no typical classification according to vegetation type is obvious. This is attributed to the calibrated parameter sets correcting for model deficiencies and data errors rather than describing the physical characteristics of the measurement site. The measured fluxes were combined into a time series of aggregated fluxes by the tile method. Calibration of TERRA/LM with respect to the averaged fluxes resulted in a range of parameter sets which all simulated the area-averaged fluxes in much better agreement with the observed fluxes than the standard parameter set of the operational model. A modified Nash-Sutcliffe measure as a coincidence criterion fell from 0.3 to a range between 0.15 and 0.28 for the latent heat flux and from 0.43 to between 0.26 and 0.36 for the sensible heat flux when the calibrated parameter sets were used instead of the standard parameters.

scholarly journals A Process-Oriented Small Lake Scheme for Coupled Climate Modeling Applications

2012 ◽  
Vol 13 (6) ◽  
pp. 1911-1924 ◽  
Author(s):  
Murray D. MacKay
Keyword(s):  
Heat Flux ◽  
Latent Heat ◽  
Land Surface ◽  
Global Climate Model ◽  
Sensible Heat Flux ◽  
Open Water ◽  
Surface Mixed Layer ◽  
Linear Temperature ◽  
Land Surface Scheme ◽  
Surface Scheme

Abstract A one-dimensional dynamic lake model is presented as a candidate for simulating small unresolved lakes within the land surface scheme of a regional or global climate model. This model is based largely on well-established process algorithms with some exceptions. The complete nonlinear surface energy balance is computed in a skin layer of arbitrary thickness in order to ensure rapid response times with the atmosphere. Turbulent mixing in the surface mixed layer is achieved through stirring and buoyancy production as well as shear production along the diurnal thermocline. The net effect of Kelvin–Helmholtz instability on thermocline structure is grossly accounted for by computing a linear temperature profile within a thermocline layer. The energetics of billowing is not considered; however, a significant thermocline leakage term is included. The model has been incorporated into the Canadian Land Surface Scheme and used to estimate regional turbulent sensible and latent heat fluxes over the Experimental Lakes Area in the boreal forest of northwestern Ontario—an area about 30% lake covered. It is demonstrated that the presence of open water has a significant effect on the net flux exchange with the atmosphere in this region. Sensible heat flux to the atmosphere is suppressed during the summer stratified period but enhanced in the fall, resulting in an increased accumulation of about 5% by the end of the open water season due to the presence of lakes. Turbulent latent heat flux to the atmosphere is more enhanced during autumn, with a final accumulation about 24% larger.

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.

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