Использование методов релаксации в модели WRF для анализа метеорологических условий в Украине за длительный период

Abstract

The possibility of using grid and spectral relaxation methods and other options in the WRF mesoscale model for long-term continuous calculations has been investigated. Results of comparison of selected me-teorological parameters with surface measurements are presented. The basic recommendations for select-ing the optimal combination of long-term calculation parameters are given. The use of the selected param-eters allowed to obtain continuous meteorological fields over a long period (several months), which are well consistent with surface measurements, retain large scale synoptic structures and have a deviation from measurements commensurate with the results of short-term simulations over corresponding time peri-od. The selected optimal combination of parameters allowed us to perform continuous calculation for the period from January 1, 2019 to November 6, 2019 without accumulating errors. In a long-run calculation of meteorological conditions in Ukraine with spatial resolution 0.15 deg. for a temperature at a height of 2 meters was obtained a mean absolute error of MAE=2,05 ºC, a correlation coefficient of Corr=0,97, for a wind speed at a height of 10 meters of MAE=1.4 m/s, of Corr=0,75, and for a wind direction at a height of 10 meters of MAE=24,6 degrees, Corr=0,66. The influence of the parametrizations of the underlying sur-face and the active soil layer on the quality of calculation of meteorological fields is studied. Using the option to update the water surface temperature allowed to reduce the MAE for the temperature from 2,17 ºС to 2,05 ºС. Each of the investigated surface models showed its advantages and disadvantages. The pa-rameterizations RUC and NOAH LSM showed good agreement with the measurements for all studied pa-rameters and can be recommended for use in long-term continuous calculations. A long calculation made it possible to describe the process of accumulation and melting of snow correctly, and made it possible to reproduce the temperature of the upper soil layer correctly as well. The paper shows that the disadvantage of long- term calculations is the inability to determine the temperature of the lower layers of the soil cor-rectly.