Cloud Cover and Satellite Images of Deforestation
研究检验了卫星图像中云层覆盖与森林砍伐数据是否独立，发现两者不独立，意味着未校正云层覆盖的森林砍伐估计可能存在偏差。
<i>Most studies of deforestation rely on land-cover data interpreted from satellite images. However, it is often difficult, particularly in moist forest areas, to obtain cloud-free images. Dropping or imputing missing values from satellite data relies on the assumption of independence of irrelevant alternatives (IIA), which implies that clouds are independent of the occurrence of forests. We test whether IIA holds for the case of Madagascar. We reject IIA for the amount of forest lost, demonstrating that estimates of deforestation and studies that use deforestation data from satellite images could potentially be biased without the proper corrections for cloud cover.</i>