Assessment of WRF Land Surface Model Performance over West Africa

Abstract

Simulations with four land surface models (LSMs) (i.e., Noah, Noah-MP, Noah-MP with ground water GW option, and CLM4) using the Weather Research and Forecasting (WRF) model at 12 km horizontal grid resolution were carried out as two sets for 3 months (December–February 2011/2012 and July–September 2012) over West Africa. The objective is to assess the performance of WRF LSMs in simulating meteorological parameters over West Africa. The model precipitation was assessed against TRMM while surface temperature was compared with the ERA-Interim reanalysis dataset. Results show that the LSMs performed differently for different variables in different land-surface conditions. Based on precipitation and temperature, Noah-MP GW is overall the best for all the variables and seasons in combination, while Noah came last. Specifically, Noah-MP GW performed best for JAS temperature and precipitation; CLM4 was the best in simulating DJF precipitation, while Noah was the best in simulating DJF temperature. Noah-MP GW has the wettest Sahel while Noah has the driest one. The strength of the Tropical Easterly Jet (TEJ) is strongest in Noah-MP GW and Noah-MP compared with that in CLM4 and Noah. The core of the African Easterly Jet (AEJ) lies around 12°N in Noah and 15°N for Noah-MP GW. Noah-MP GW and Noah-MP simulations have stronger influx of moisture advection from the southwesterly monsoonal wind than the CLM4 and Noah with Noah showing the least influx. Also, analysis of the evaporative fraction shows sharp gradient for Noah-MP GW and Noah-MP with wetter Sahel further to the north and further to the south for Noah. Noah-MP-GW has the highest amount of soil moisture, while the CLM4 has the least for both the JAS and DJF seasons. The CLM4 has the highest LH for both DJF and JAS seasons but however has the least SH for both DJF and JAS seasons. The principal difference between the LSMs is in the vegetation representation, description, and parameterization of the soil water column; hence, improvement is recommended in this regard.

Potential effects of Land Use Land Cover Change on streamflow over the Sokoto Rima River Basin

“…The partitioning of net radiation into Latent Heat (LH) and Sensible Heat (SH) fluxes can determine how wet the soil would be ( Achugbu et al., 2020 ). This splitting up of surface energy critically depends on the moisture content of the soil ( Klein et al., 2016 ).…”

The impacts of land use and land cover change on biophysical processes in West Africa using a regional climate model experimental approach

“…During the summer, the tropical easterly jet (TEJ), which is connected to the outflow of the South Asian monsoon, spreads through WA (Akinsanola and Zhou, 2020). Furthermore, the strength and the location of the systems could affect the precipitation in West Africa (Cook, 1999; Achugbu et al ., 2020). These dynamic processes produce a strong coupling between the earth's surface and the atmosphere over WA, hence, showing that a little disturbance or alteration of the land surface can grow vertically in the atmosphere.…”

Local and non‐local atmospheric effects of abnormal soil moisture over Indochina during May and June

“…Moreover, the land surface scheme used is the Community Land Model (CLM) version 4 (Dai et al ., 2003), which is developed by the National Center for Atmospheric Research, USA, including sophisticated simulation of biogeophysics, hydrology, biogeochemistry, and vegetation dynamics (Oleson et al ., 2010; Lawrence et al ., 2011). CLM has a soil column of ten layers, including 10 depths from 0.0–3.433 m and calculates overland flow with a simple conceptual TOPMODEL (Topography based Hydrological Model; Niu et al ., 2005) approach to parameterize the surface runoff, which is widely used in land surface models (Li et al ., 2011; Achugbu et al ., 2020). Compared with the relatively simple land surface schemes in WRF, the CLM improves the simulation of surface processes at different spatial scales and is particularly suitable for regional applications (Lu and Kueppers, 2012; Achugbu et al ., 2020; Xu et al ., 2020; Zhang et al ., 2020b).…”

“…CLM has a soil column of ten layers, including 10 depths from 0.0–3.433 m and calculates overland flow with a simple conceptual TOPMODEL (Topography based Hydrological Model; Niu et al ., 2005) approach to parameterize the surface runoff, which is widely used in land surface models (Li et al ., 2011; Achugbu et al ., 2020). Compared with the relatively simple land surface schemes in WRF, the CLM improves the simulation of surface processes at different spatial scales and is particularly suitable for regional applications (Lu and Kueppers, 2012; Achugbu et al ., 2020; Xu et al ., 2020; Zhang et al ., 2020b). The six‐hourly CFSR/CFSv2 data were taken as the initial and boundary conditions.…”