جستجوی مقالات مرتبط با کلیدواژه "merra" در نشریات گروه "زمین شناسی"

Estimating air temperature plays an important role in many water and energy balance calculations, hydrological modeling, meteorological and agricultural studies. Changes in air temperature influence on plant growth and many other components at the interface between earth surface and atmosphere. The most common sources for air temperature time series are meteorological stations. However, meteorological networks are sparse in complex terrains, such as mountains. This is mainly due to difficulties with the installation and maintenance of the stations. The air temperature can also be calculated using climate model and reanalysis datasets. The purpose of this study was to introduce two meteorological reanalysis databases: the European Center for Medium-Range Weather Forecasts (ECMWF) and Modern-Era Retrospective Analysis for Research and Applications (MERRA), and evaluation of their performance in estimating daily maximum, minimum and average air temperature. In this regard, maximum, minimum and average air temperature data at daily scale for a period of 14 years from 2003 to 2016 (5114 days) were obtained from 12 temperature measurement stations in Helleh river basin area in south of Iran and the Persian Gulf coasts. The elevation correction and downscaling temperature based on modeled lapse rate are used for correcting two meteorological reanalysis datasets. The correlation coefficient (CC), mean error (ME) and squared mean of errors (RMSE) were used to evaluate the presented datasets. The results showed that the compliance rate of reanalysis datasets in all parameters of maximum, minimum, and average air temperature are appropriate, but the ECMWF-ERA-Interim version dataset is much better than the MERRA version 2 dataset. The correlation coefficients for all parameters of maximum, minimum and average air temperature are more than 0.9. Also, the performance of both datasets in estimating the average air temperature at daily scale is better than the maximum and minimum air temperature at daily scale. Both databases are also underestimated in estimating maximum temperature data and overestimated in estimating minimum data. The average air temperature at daily scale is estimated slightly warmer (0.4°C) from the ECMWF-ERA-Interim version dataset, while the MERRA dataset of version 2 estimates the mean of air temperature colder (-0.5°C). Finally, the use of daily air temperature parameters (maximum, minimum and average) of the ECMWF ERA-Interim dataset is more preferable than MERRA version 2 dataset. Considering the proper performance of reanalysis datasets and using their advantages, we suggest evaluating other meteorological parameters.