We analyzed a 2-year time series of meteorological data (January 2011–December 2012) from three automatic weather stations on Laohugou glacier No. 12, western Qilian Mountains, China. Air temperature, humidity and incoming radiation were significantly correlated between the three sites, while wind speed and direction were not. In this work, we focus on the effects of clouds on other meteorological parameters and on glacier melt. On an average, ~18% of top-of-atmosphere shortwave radiation was attenuated by the clear-sky atmosphere, and clouds attenuated a further 12%. Most of the time the monthly average increases in net longwave radiation caused by clouds were larger than decreases in net shortwave radiation but there was a tendency to lose energy during the daytime when melting was most intense. Air temperature and wind speed related to turbulent heat flux were found to suppress glacier melt during cloudy periods, while increased water vapor pressure during cloudy days could enhance glacier melt by reducing energy loss by latent heat. From these results, we have increased the physical understanding of the significance of cloud effects on continental glaciers.

The main objective of this article is to study the effect of 2D coupled mode freeconvection with surface radiation on the fluid flow behavior in an air filled partitionedand shallow cavity subjected to isothermal or insulated boundary conditions. Thedimensionless governing equations under Boussinesq approximation are coupled with aradiative model through the boundaries conditions and solved by the finite volume method.The numerical results are discussed in terms of streamlines, isotherms, convective andradiative Nusselt numbers along the cover plate for various aspect ratios (a, b and c), emissivities andRayleigh number. These results highlighted the condition of the enclosure performance andrevealed among other that isothermal boundaries induce better convective heat exchangecompared to adiabatic cases. Also, it is noticed that varying aspect ratio(a) causesstrong influence on both Nusselt numbers compared to the aspect ratios (b) and (c). The increase of(ϵo) raisesNuconvand decreases Nuradslightly. Whereas, an increase of (ϵC) leads to minorchanges in Nuradwhen (b) or(c) vary,this effect becomes appreciable with increasing (a).