Implications of the day versus night differences of water vapor, carbon monoxide, and thin cloud observations near the tropical tropopause

Abstract

There are some interesting day versus night differences in the water vapor and carbon monoxide concentrations near the tropopause over tropical land and ocean from 4 years of EOS Microwave Limb Sounder (MLS) observations. To interpret these differences, the diurnal cycle of deep convection reaching near tropical tropopause summarized from a decade of tropical rainfall measuring mission (TRMM) observations. We also present the diurnal cycle of the cold point tropopause temperature and height derived from 2 years of constellation observing system for meteorology ionosphere and climate (COSMIC) GPS temperature profiles, the day versus night differences of occurrence of thin clouds from 2 years of cloud‐aerosol lidar and infrared pathfinder satellite observations (CALIPSO) and 16 years of stratospheric aerosol and gaseous experiment (SAGE) II. In the tropical upper troposphere, day versus night differences of water vapor and carbon monoxide are consistent with the diurnal cycle of the vertical transport of water vapor and carbon monoxide–rich air from the surface by deep convection. However, in the tropical tropopause layer (TTL) over land, day versus night differences of water vapor concentration are more consistent with the diurnal variations of temperature in a saturated TTL, which is related to the diurnal cycle of cooling in the TTL induced by deep convection. The day versus night differences of occurrences of thin clouds in the TTL are also consistent with the freeze drying, controlled by the diurnal cycles of temperature in the TTL.