Improvement of Cloud Radiative Forcing and Its Impact on Weather Forecasts
نویسندگان
چکیده
The global numerical weather prediction model GRAPES at the National Meteorological Center of the China Meteorological Administration is subject to substantial systematic discrepancies from satellite-retrieved cloud cover, cloud water contents, and radiative fluxes. In particular, GRAPES produces insufficient total cloud cover and liquid water amounts and, consequently, greatly underestimates cloud radiative forcings and causes substantial radiation budget errors. Along with updates of several physics components, new parameterization schemes are incorporated in this study to more realistically represent cloud-radiation interactions. These schemes include predictions for cloud cover, liquid water, and effective radius as well as radiative effects of partial clouds and in-cloud inhomogeneity. As a result, radiation fluxes and cloud radiative forcings at both the surface and top of the atmosphere agree much better with the best available satellite data. The global mean model biases in most radiation fluxes using the new physics are approximately three times smaller than using the original physics. These improvements enhance the model weather forecast skills for key surface variables, including precipitation and 2 m temperature, and for height and temperature in the lower troposphere. Although nontrivial biases still exist, this study nonetheless represents the first essential step toward correcting the radiation imbalance before tackling other formulation deficiencies so that significantly enhanced GRAPES weather forecast skills can eventually be achieved.
منابع مشابه
Potential aerosol indirect effects on atmospheric circulation and radiative forcing through deep convection
[1] Aerosol indirect effects, i.e., the interactions of aerosols with clouds by serving as cloud condensation nuclei or ice nuclei constitute the largest uncertainty in climate forcing and projection. Previous IPCC reported negative aerosol indirect forcing, which does not account for aerosolconvective cloud interactions because the complex processes involved are poorly understood and represent...
متن کاملA survey on impact of cloud computing security challenges on NFV infrastructure and risks mitigation solutions
Increased broadband data rate for end users and the cost of resource provisioning to an agreed SLA in telecom service providers, are forcing operators in order to adhere to employment Virtual Network Functions (VNF) in an NFV solution. The newly 5G mobile telecom technology is also based on NFV and Software Define Network (SDN) which inherit opportunities and threats of such constructs. Thus a ...
متن کاملImproving aerosol distributions below clouds by assimilating satellite-retrieved cloud droplet number.
Limitations in current capabilities to constrain aerosols adversely impact atmospheric simulations. Typically, aerosol burdens within models are constrained employing satellite aerosol optical properties, which are not available under cloudy conditions. Here we set the first steps to overcome the long-standing limitation that aerosols cannot be constrained using satellite remote sensing under c...
متن کامل10 Bretherton & Hartmann.indd
The climatological distribution of clouds is tightly coupled to large-scale circulation. Net cloud radiative forcing is mainly the result of boundary layer clouds in large-scale subsidence. Deep convective cloud systems exert longand shortwave cloud forcing that nearly cancel out each other. The extent of this cancellation depends strongly on the vertical motion profi le, suggesting that if the...
متن کاملCloud Impacts on Pavement Temperature and Shortwave Radiation
Forecast systems provide decision support for end-users ranging from the solar energy industry to municipalities concerned with road safety. Pavement temperature is an important variable when considering vehicle response to various weather conditions. A complex, yet direct relationship exists between tire and pavement temperatures. Literature has shown that as tire temperature increases, fricti...
متن کامل