Influence of microphysical schemes on atmospheric water in the Weather Research and Forecasting model

Abstract

Abstract. This study examines how different microphysical parameterization schemes influence orographically induced precipitation and the distributions of hydrometeors and water vapour for midlatitude summer conditions in the Weather Research and Forecasting (WRF) model. A high-resolution two-dimensional idealized simulation is used to assess the differences between the schemes in which a moist air flow is interacting with a bell-shaped 2 km high mountain. Periodic lateral boundary conditions are chosen to recirculate atmospheric water in the domain. It is found that the 13 selected microphysical schemes conserve the water in the model domain. The gain or loss of water is less than 0.81 % over a simulation time interval of 61 days. The differences of the microphysical schemes in terms of the distributions of water vapour, hydrometeors and accumulated precipitation are presented and discussed. The Kessler scheme, the only scheme without ice-phase processes, shows final values of cloud liquid water 14 times greater than the other schemes. The differences among the other schemes are not as extreme, but still they differ up to 79 % in water vapour, up to 10 times in hydrometeors and up to 64 % in accumulated precipitation at the end of the simulation. The microphysical schemes also differ in the surface evaporation rate. The WRF singlemoment 3-class scheme has the highest surface evaporation rate compensated by the highest precipitation rate. The different distributions of hydrometeors and water vapour of the microphysical schemes induce differences up to 49 W m −2 in the downwelling shortwave radiation and up to 33 W m −2 in the downwelling longwave radiation.

Evaluating the present annual water budget of a Himalayan headwater river basin using a high‐resolution atmosphere‐hydrology model

“…In an investigation of the influence of microphysical schemes on precipitation, Cossu and Hocke [] show that most of these schemes (including WRF Single‐moment 3‐class scheme and Thompson), with the exception of Kessler, have no extreme differences, though they differ in amount of water vapor and accumulated precipitation. The choice of microphysical scheme has important consequences for water phase component, hydrometeor distribution, and precipitation.…”

“…[] showed improved representation of precipitation in a high‐resolution (2 km) dynamical simulation when compared to satellite products. Cossu and Hocke [] compared 13 WRF parameterization schemes over a bell‐shaped mountain and found that the choice of microphysical scheme has important consequences for water phase component, hydrometeor distribution, and precipitation. At high resolution, and with selection of the proper parameterizations, RCMs have demonstrated the capability to capture the statistical features of orographic precipitation such as seasonality, relative intensity, and precipitation phase even if the timing of specific events is off due to internal model variability [ Barstad and Caroletti , ; Rasmussen et al ., , ].…”

Cloud Resolving WRF Simulations of Precipitation and Soil Moisture Over the Central Tibetan Plateau: An Assessment of Various Physics Options

“…WRF offers a broad spectrum of parameterization options, by including multiple schemes for each of the microphysics, land surface, planetary boundary layer (PBL), cumulus, and radiation processes. Studies have indicated that the optimal scheme highly depends on the weather or climate regimes and the application scales, and no scheme universally performs the best (Jankov et al, 2005;Gallus & Bresch, 2006;Cossu & Hocke, 2014;Song & Sohn, 2018). Similar to other regions, the choice of schemes over the TP also depends on the study's specific purpose (Maussion et al, 2011).…”

Atmospheric water parameters measured by a ground‐based microwave radiometer and compared with the WRF model

“…It is known that simulations with the same configuration and initial conditions but with different microphysical schemes can produce different results (Jankov et al, 2005(Jankov et al, , 2009Otkin and Greenwald, 2008;Mercader et al, 2010;Awan et al, 2011). A comparison of 13 microphysical schemes for an idealized WRF model simulation can be found in Cossu and Hocke (2014).…”