Land Hydrology Division, Space Applications Centre (ISRO), Ahmedabad, India.
Indian Institute of Remote Sensing (IIRS), Dehradun, India.
Isotopes Environ Health Stud. 2023 Jun;59(3):248-268. doi: 10.1080/10256016.2023.2212834. Epub 2023 May 21.
Rainforests play an important role in hydrological and carbon cycles, both at regional and global scales. They pump large quantities of moisture from the soil to the atmosphere and are major rainfall hotspots of the world. Satellite-observed stable water isotope ratios have played an essential role in determining sources of moisture in the atmosphere. Satellites provide information about the processes involving vapour transport in different zones of the world, identifying sources of rainfall and distinguishing moisture transport in monsoonal systems. This paper focuses on major rainforests of the world (Southern Amazon, Congo and Northeast India) to understand the role of continental evapotranspiration in influencing tropospheric water vapour. We have used satellite measurements of HHO/HO from Atmospheric InfraRed Sounder (AIRS), evapotranspiration (ET), solar-induced fluorescence (SIF), precipitation (P), atmospheric reanalysis-derived moisture flux convergence (MFC) and wind to discern the role of ET in influencing water vapour isotopes. A global map of the correlation between H and ET-P flux indicates that densely vegetated regions in the tropics show the highest positive correlation (r > 0.5). Using mixing models and observations of specific humidity and isotopic ratio over these forested regions, we discern the source of moisture in pre-wet and wet seasons.
热带雨林在区域和全球尺度的水文和碳循环中都起着重要作用。它们从土壤中大量抽取水分并输送到大气中，是世界上主要的降雨热点地区。卫星观测到的稳定水同位素比在确定大气中水分来源方面发挥了重要作用。卫星提供了有关不同地区水汽输送过程的信息，确定了降雨的来源，并区分了季风系统中的水汽输送。本文重点研究了世界上的主要雨林（南亚马孙、刚果和印度东北部），以了解大陆蒸散在影响对流层水汽中的作用。我们使用了大气红外探测器（AIRS）测量的 HHO/HO、蒸散量（ET）、太阳诱导荧光（SIF）、降水（P）、大气再分析得出的水汽通量辐合（MFC）和风的卫星测量数据，以辨别蒸散对水汽同位素的影响。H 和 ET-P 通量之间相关性的全球图表明，热带地区植被茂密的地区显示出最高的正相关性（r>0.5）。利用混合模型和这些森林地区的比湿和同位素比的观测结果，我们辨别了干湿两季水分的来源。
