S17

Tracer methods in catchment and critical zone hydrology

Stable and radioactive isotopes as well as other natural and artificial tracers are useful tools to study water flow, solute transport and transformation processes in hydrology. They are of particular importance for identifying sources of water, contaminants and nutrients, flow paths, transport properties and geochemical processes, and for quantifying important hydrological variables, such as water transit times. We invite contributions that demonstrate the application and recent developments of isotope and other tracer techniques in catchment hydrology and the critical zone. This includes field and modelling studies in the areas of surface-groundwater interactions, unsaturated and saturated zone, rainfall-runoff processes, ecohydrology, nutrient or contaminant export, or other relevant processes in catchments and the critical zone.

Convener: Andrea L. Popp | Co-Conveners: David Hannah, Christine Stumpp, Przemyslaw Wachniew, Maki Tsujimura, Giovanny Mosquera, ZHONGHE PANG
Orals
| Wed, 01 Jun, 08:30–15:00|Room Rondelet 2
Posters
| Attendance Wed, 01 Jun, 15:00–16:30|Poster area

Orals: Wed, 01 Jun | Room Rondelet 2

Chairpersons: Maki Tsujimura, Giovanny Mosquera
08:30–08:45
|
IAHS2022-561
Fen Zhang, Tianming Huang, and Zhonghe Pang

Defining moisture sources and evolution of precipitation is significant for further exploration of complex hydro-climatic interactions, especially under global warming with alternations of evapotranspiration capacity and precipitation moisture source structure. As a sensitive indicator, dexcess has been widely used to quantify the proportion of recycled vapor to precipitation (fre). However, existing models ignore taking transpiration vapor into account and the calculated fre tends to be lower than the true value. Herein, it was modified with transpiration vapor considered and applied in Guyuan, China located in a monsoon marginal zone with complex precipitation moisture sources. After modification, the estimated annual average fre was increased from 7.5% to 14.8%. This study highlights the contribution of transpiration vapor to precipitation and provides more information on the formation and evolution of precipitation to better serve future hydro-climatic research. The article has been published in the Geophysical Research Letters (https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021GL095909).

Figure 1. Conceptual diagram of a modified d-excess-based model emphasizing d-excess for three end-members (advected, evaporation, and transpiration vapor) of precipitation moisture sources.

Figure 1. Conceptual diagram of a modified d-excess-based model emphasizing d-excess for three end-members (advected, evaporation, and transpiration vapor) of precipitation moisture sources.

Figure 2. (a) Map showing the locations of Guyuan precipitation station. (b) Main moisture sources of precipitation in China. (c) Distribution of annual mean monthly precipitation and air temperature in Guyuan.

Figure 2. (a) Map showing the locations of Guyuan precipitation station. (b) Main moisture sources of precipitation in China. (c) Distribution of annual mean monthly precipitation and air temperature in Guyuan.