Our team has been researching the landscape evolution of Saharan Africa and Arabia and the nature of the wet climatic periods. Were the wet periods are related to the intensification of monsoons in interglacial periods or paleo-westerlies in glacial periods? Our team addresses these questions by mapping the distribution of geomorphic features left behind the wet periods (e.g., spring mounds, paleolakes, theater head valleys, etc.), estimating recharge temperatures from noble gas concentrations in groundwater, age dating groundwater and lake deposits using chlorine-36, krypton-81, and U-Th dating techniques, and analyzing the stable isotopic composition (O, H) of the groundwater.