Journal of Geophysical Research: Atmospheres

Cloud cover conditions and stability of the Western Ghats montane wet forests

Authors


Abstract

[1] Using remote sensing data from multiple satellites and numerical simulations we addressed the hypothesis that the Western Ghats tropical montane wet forests in southwest India are hydrometeorologically stressed and lowland deforestation has decreased cloud cover and precipitation. We generated water cloud and Leaf Area Index climatologies for a 6 year period and answered the following questions: (1) what are the diurnal and seasonal variations of water clouds, (2) what is the relationship between cloud cover and topography, (3) where are potential locations of the tropical montane wet forests, (4) what are the current hydrometeorological conditions over the identified tropical montane wet forests, and (5) what is the sensitivity of cloud cover and precipitation over the montane wet forests to lowland deforestation? The study found that (1) strong correlations between climatological precipitation and cloud frequency were present thereby indicating that higher spatial and temporal resolution cloud frequency is a good indicator of hydrometeorological conditions; (2) cloud frequency was lower in the dry season (10–25%) and higher in the monsoon seasons (40–45%); (3) a morning-afternoon pattern in cloud cover exists during both the dry and wet seasons; (4) morning cloud cover decreased from October to January with afternoon cloud cover similarly decreasing but with higher values than the morning cloud cover; (5) cloud cover generally increased with elevation; (6) 39%, 70%, 47% and 42% of the clouds intersected the mountains during March and May 2007 and February and April 2008, respectively; (7) our maps showing regions with conditions suitable to sustain tropical montane wet forests successfully identified known montane biodiversity hot spots; and (8) simulations showed an increase of afternoon cloud cover and dry season precipitation but reduced cloud immersion over the montane forests with lowland deforestation.