Paper Submitted to NATURE GEOSCIENCES
"Do Clouds Follow Deforestation Over the Amazon?" (Supplementary materials)
A movie of cloud sequences (cloud.avi) derived from GOES-7 visible and infrared images during the period of 13-26 August 1994 over the study domain in Rondonia. There are total 689 images with one frame every 30 minutes. The upper panel shows the cloud-top albedo based on visible channel of GOES-7, and the lower panel shows the cloud-top brightness temperature (K) based on IR channel 8 of the GOES-7 satellite. The time is GMT (Julian) day:hour:minute with local time (LST) 4 hours behind GMT. "forest (o)" and "pasture (+)" indicate the locations of sounding measurements. The movie shows the day time images 11:01 - 17:31 (LST). k in the movie is the sequence number of the images, k=1,...,689. The movie in avi format is located at the URL (see below) for free download.
[[http://web.mit.edu/hydrology/Public/CloudMovie/cloud.avi"Cloud movie"]] (Warning: large file ~410 MB)
Research Interests
1. Deforestation and Climate Change over Amazonia
This research investigates the impact of land surface variability on the distributions of cloudiness and rainfall over deforested Amazonia. Our earlier modeling studies of the role of deforestation at local scale in shaping the distributions of rainfall and cloudiness over Amazonia have revealed that the synoptic stability and wind conditions dominate the rainfall processes while the land surface heterogeneity due to deforestation may be responsible for the enhancement of cloudiness through mechanisms of mesoscale circulations induced by the contrast between forested and deforested patches and/or variability in PBL turbulent flow when the synoptic forcing is relatively weak. The on-going research focuses on detecting the significance of differences in rainfall over forest and deforested areas over Amazonia; evaluating the statistical correlation between cloudiess and land cover patterns; identifying the cloud types using data products from TRMM and other sources.
2. Exchange of energy and mass at land-atmosphere interface
A novel method has been developed for estimating surface heat fluxes from time series observations of surface variables such as temperature at a single level. The theory is based on the fact that heat and mass transport in the soil media and atmospheric boundary layer are often dominated by one-dimensional diffusion processes so that there exist unique relationships between the time functions of surface fluxes and the time history of the corresponding surface variables (e.g. surface temperature). This new method avoids the measurements of profiles of meteorological variables required by the traditional methods of estimating surface fluxes. This method is particularly convenient for evaluating surface energy balance using remote sensing measurements. Applications of the method include calculating global maps of surface heat fluxes from reanalysis data of surface variables.
Contact Information
Jingfeng Wang, Sc.D.
Massachusetts Institute of Technology
Ralph M. Parsons Laboratory, 48-330B
Cambridge, MA 02139
ph: +1 617 253 9874
fx: +1 617 258 8850
Email