Stratiform anvils in the upper tropical troposphere were simulated to determine the sensitivities of their radiative properties to the presence of small ice crystals. Cloud evolution was modelled in a one-dimensional (vertical) framework incorporating an updraft, deposition, sublimation, sedimentation, nucleation, and radiation. The sensitivities of cloud radiative forcing, albedo, emissivity, ...

Present-day Arctic and Antarctic radiation budgets of the National Center for Atmospheric Research Community Climate Model version 3 (CCM3) are presented. The CCM3 simulation is from a prescribed and interannually varying sea surface temperature integration from January 1979 through August 1993. Earth Radiation Budget Experiment (ERBE) data from 1985 through 1989 are used for validation of top-...

The quasi-equilibrium tropical circulation model (QTCM1) is implemented and tested. The formulation, described by Neelin and Zeng, uses a Galerkin framework in the vertical, but with basis functions tailored to quasi-equilibrium deep convective physics via analytical solutions. QTCM1 retains a single vertical structure of temperature and humidity. For a balanced treatment of dynamics and subgri...

Increases in anthropogenic aerosols in the atmosphere tend to increase the reflectance of solar (shortwave) radiation from water clouds, which can lead to lower surface temperatures. Here an opposing effect whereby aerosols increase the longwave emissivity of thin clouds that adds to the warming of the earth’s surface, is discussed. The latter effect may be particularly important in the Arctic,...

Due to computational expense, the radiation schemes in many weather and climate models are called infrequently in time and/or on a reduced spatial grid. The former can lead to a lag in the diurnal cycle of surface temperature, while the latter can lead to large surface temperature errors at coastal land points due to surface fluxes computed over the ocean being used where the skin temperature a...

The optical properties of sea-salt aerosol have been parameterized at shortwave and longwave wavelengths. The optical properties were parameterized in a simple functional form in terms of the ambient relative humidity based on Mie optical property calculations. The proposed parameterization is tested relative to Mie calculations and is found to be accurate to within a few percent. In the parame...

Our aim is to provide an observational reference for the evaluation of the surface and boundary layer parameterizations used in large-scale models using the remarkable long-term Canadian Prairie hourly dataset. First we use shortwave and longwave data from the Baseline Surface Radiation Network (BSRN) station at Bratt’s Lake, Saskatchewan, and clear sky radiative fluxes from ERA-Interim, to sho...

An objective method was developed to analyze longwave and shortwave trough lines in wind field data using different methods, given that these trough lines were researched in different ways. Longwave trough lines were analyzed by locating the cyclonic center and filtering candidate trough points simultaneously; the candidate longwave trough points were then traced based on distance and angle con...

Thermal radiation significantly impacts the energy balance of human beings, and is usually assessed via mean radiant temperature Tmrt. The longwave down-welling radiation (LDR) and the up-welling from ground (LUR) are rarely measured, but are in the same order of magnitude as daily means of shortwave irradiation. This study evaluates simple, but theoretically based algorithms for LDR and LUR by...

Solar diffuse radiation data including global radiation, shortwave and longwave balances, net radiation and sunshine hours have been extensively analyzed to study the variation of diffuse radiation with turbidity and cloud discharges appearing in the form of atmospherics over the tropics. Results of surface radiation measurements at Calcutta, Poona, Delhi and Madras are presented together with ...