The regional scale impact of land cover change simulated with a climate model

摘要

A series of 17-year integrations using the NCAR CCM3 (at about 2.8° * 2.8° resolution) were performed to investigate the regional-scale impact of land cover change. Our aim was to determine the impact of historical land cover change on the regional-scale climate over the regions where most change occurred: Europe, India and China. The change from natural to current land cover was estimated using BIOME3 to predict the natural vegetation type, and then using remotely sensed data to estimate the locations where land cover had been changed through human activity. Results show statistically significant changes in the 15-year averaged 1000 hPa wind field, mean near-surface air temperature, maximum near-surface air temperature and the latent heat flux over the regions where land cover change was imposed. These changes disappeared if the land cover over a particular region was omitted, indicating that our results cannot be explained by model variability. An analysis of changes on an averaged monthly time scale showed large changes in the maximum daily temperature in (Northern Hemisphere) summer and little change in the minimum daily temperature, resulting in changes in the diurnal temperature range. The change in the diurnal temperature range could be positive or negative depending on region, time of year and the precise nature of the land cover changes. Our results indicate that the inclusion of land cover change scenarios in simulations of the 20th century may lead to improved results. The impact of land cover changes on regional climates also provides support for the inclusion of land surface models that can represent future land cover changes resulting form an ecological response to natural climate variability or increasing carbon dioxide.