TY - JOUR
T1 - A surface temperature and moisture intercomparison study of the Weather Research and Forecasting model, in-situ measurements and satellite observations over the Atacama Desert
AU - Fonseca, Ricardo
AU - Zorzano-Mier, María Paz
AU - Azua-Bustos, Armando
AU - González-Silva, Carlos
AU - Martín-Torres, Javier
N1 - Funding Information:
information Dubai Future Foundation, MBR023The authors would like to thank the High Performance Computing Center North (HPC2N) for providing the computer resources needed to perform the numerical simulations presented in this paper. The MODIS C11 data product was retrieved from the online Data Pool, courtesy of the NASA Land Processes Distributed Active Archive Center (LP DAAC), United States Geological Survey (USGS)/Earth Resources Observation and Science (EROS) Center, Sioux Falls, South Dakota (https://lpdaac.usgs.gov/data_access/data_pool). This project received seed funding from the Dubai Future Foundation through the Guaana.com open research platform (MBR023). We would like to thank three anonymous reviewers for their detailed and insightful comments and suggestions that helped to improve the quality of the paper. RMF set up and carried out the numerical simulations with critical inputs from MPZM. AAB and CGS were responsible for the field campaigns and the retrieval of in-situ observational data. The model results were interpreted by RMF and MPZM with inputs from JMT. All authors contributed to the writing of the manuscript. The authors declare that they have no conflict of interest.
Publisher Copyright:
© 2019 Royal Meteorological Society
PY - 2019/7
Y1 - 2019/7
N2 - Good knowledge of the environmental conditions of deserts on Earth is relevant for climate studies. The Atacama Desert is of particular interest as it is considered to be the driest region on Earth. We have performed simulations using the Weather Research and Forecasting (WRF) model over the Atacama Desert for two week-long periods in the austral winter season coincident with surface temperature and relative humidity in-situ observations at three sites. We found that the WRF model generally overestimates the daytime surface temperature, with biases of up to 11°C, despite giving a good simulation of the relative humidity. In order to improve the agreement with observed measurements, we conducted sensitivity experiments in which the surface albedo, soil moisture content and five tuneable parameters in the Noah Land Surface Model (namely soil porosity, soil suction, saturated soil hydraulic conductivity, the b parameter used in hydraulic functions and the quartz fraction) are perturbed. We concluded that an accurate simulation is not possible, most likely because the Noah Land Surface Model does not have a groundwater table that may be shallow in desert regions. The WRF-predicted land surface temperature is also evaluated against that estimated from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument. While at night the satellite-derived and ground-based measurements are generally in agreement, during the day MODIS estimates are typically lower by as much as 17°C. This is attributed to the large uncertainty in the MODIS-estimated land surface temperatures in arid and semi-arid regions. The findings of this work highlight the need for ground-based observational networks in remote regions such as the Atacama Desert where satellite-derived and model products may not be very accurate.
AB - Good knowledge of the environmental conditions of deserts on Earth is relevant for climate studies. The Atacama Desert is of particular interest as it is considered to be the driest region on Earth. We have performed simulations using the Weather Research and Forecasting (WRF) model over the Atacama Desert for two week-long periods in the austral winter season coincident with surface temperature and relative humidity in-situ observations at three sites. We found that the WRF model generally overestimates the daytime surface temperature, with biases of up to 11°C, despite giving a good simulation of the relative humidity. In order to improve the agreement with observed measurements, we conducted sensitivity experiments in which the surface albedo, soil moisture content and five tuneable parameters in the Noah Land Surface Model (namely soil porosity, soil suction, saturated soil hydraulic conductivity, the b parameter used in hydraulic functions and the quartz fraction) are perturbed. We concluded that an accurate simulation is not possible, most likely because the Noah Land Surface Model does not have a groundwater table that may be shallow in desert regions. The WRF-predicted land surface temperature is also evaluated against that estimated from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument. While at night the satellite-derived and ground-based measurements are generally in agreement, during the day MODIS estimates are typically lower by as much as 17°C. This is attributed to the large uncertainty in the MODIS-estimated land surface temperatures in arid and semi-arid regions. The findings of this work highlight the need for ground-based observational networks in remote regions such as the Atacama Desert where satellite-derived and model products may not be very accurate.
KW - field campaigns < 1. Tools and methods
KW - geophysical sphere
KW - local or boundary layer scale < 2. Scale, Dryland/desert < 4
KW - regional and mesoscale modelling < 1. Tools and methods
KW - remote sensing < 1. Tools and methods
KW - tropics < 5. Geographic/climatic zone
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U2 - 10.1002/qj.3553
DO - 10.1002/qj.3553
M3 - Article
AN - SCOPUS:85066103855
VL - 145
SP - 2202
EP - 2220
JO - Quarterly Journal of the Royal Meteorological Society
JF - Quarterly Journal of the Royal Meteorological Society
SN - 0035-9009
IS - 722
ER -