Tropical montane cloud forests (TMCFs) depend on predictable, frequent, and prolonged immersion in cloud. Clearing upwind lowland forest alters surface energy budgets in ways that influence dry season cloud fields and thus the TMCF environment. Landsat and Geostationary Operational Environmental Satellite imagery show that deforested areas of Costa Rica's Caribbean lowlands remain relatively cloud-free when forested regions have well-developed dry season cumulus cloud fields. Further, regional atmospheric simulations show that cloud base heights are higher over pasture than over tropical forest areas under reasonable dry season conditions. These results suggest that land use in tropical lowlands has serious impacts on ecosystems in adjacent mountains.

The Clouds and the Earth's Radiant Energy System (CERES) is part of NASA's Earth Observing System (EOS). CERES objectives include the following. 1) For climate change analysis, provide a continuation of the Earth Radiation Budget Experiment (ERBE) record of radiative fluxes at the top-of-the-atmosphere (TOA), analyzed using the same techniques as the existing ERBE data. 2) Double the accuracy of estimates of radiative fluxes at TOA and the earth's surface; 3) Provide the first long-term global estimates of the radiative fluxes within the earth's atmosphere. 4) Provide cloud property estimates collocated in space and time that are consistent with the radiative fluxes from surface to TOA. In order to accomplish these goals, CERES uses data from a combination of spaceborne instruments: CERES scanners, which are an improved version of the ERBE broadband radiome

[1] The current study provides new insights into the coupling of land use in lowland and premontane regions (i.e., regions below 1000 m) and orographic cloud formation over the Monteverde cloud forests. Rawinsondes launched during the Land Use Cloud Interaction Experiment (LUCIE) together with those from the National Centers for Environmental Prediction (NCEP) provided profiles that were used to drive the Colorado State University Regional Atmospheric Modeling System (CSU RAMS) model, which simulated three realistic land use scenarios (pristine forests, current conditions and future deforestation). For current conditions, the model-simulated clouds were compared against those observed at hourly intervals by the Geostationary Environmental Observational Satellite-East (GOES E) satellite. The model performed best on 6 different days. The model-simulated profiles of dew point and air temperatures were compared with the observed profiles from rawinsondes for these days. There was generally very good agreement below 700 mb, the region of the atmosphere most crucial to the cloud forests. The average model simulations for the 6 days show that when the lowland and premontane regions were completely forested, the orographic cloud bank intersected the mountains at the lowest elevations, covered the largest land surface area and remained longest on the surface in the montane regions. Deforestation has decreased the cloud forest area covered with fog in the montane regions by around 5-13% and raised the orographic cloud bases by about 25-75 m in the afternoon. The model results show that further deforestation in the lowland and premontane regions would lead to around 15% decrease in the cloud forest area covered with fog and also raise the orographic cloud base heights by up to 125 m in the afternoon. The simulations show that deforestation in the lowland and premontane regions raises surface sensible heat fluxes and decreases latent heat fluxes. This warms the air temperature and results in a lower dew point temperature of air masses that blow over the lowland and premontane regions. These air masses when lifted form the orographic cloud bank at higher elevations.