The seasonality of deuterium excess in non-polar precipitation
|Author:||Xia, Zhengyu1,2; Welker, Jeffrey M.3,4; Winnick, Matthew J.2|
1Key Laboratory of Geographical Processes and Ecological Security in Changbai Mountains, Ministry of Education, School of Geographical Sciences, Northeast Normal University, Changchun, China
2Department of Geosciences, University of Massachusetts Amherst, Amherst, MA, USA
3Department of Biological Sciences, University of Alaska Anchorage, Anchorage, AK, USA
4UArctic, Ecology and Genetics Research Unit, University of Oulu, Oulu, Finland
|Online Access:||PDF Full Text (PDF, 4.3 MB)|
|Persistent link:|| http://urn.fi/urn:nbn:fi-fe202301235086
American Geophysical Union,
|Publish Date:|| 2023-01-23
The deuterium excess (d-excess) of precipitation varies seasonally at sites across the globe, an observation that has often been linked to seasonal changes in oceanic evaporation conditions, continental moisture recycling, and subcloud raindrop re-evaporation. However, there have been very few studies to quantify and evaluate the relative importance of these processes. Here, we revisit the mechanisms of precipitation d-excess seasonality in low-latitudes and mid-latitudes through a new analysis of precipitation isotope databases along with climate reanalysis products and moisture tracking models. In low-latitudes, the raindrop re-evaporation effect, indicated by local relative humidity, exerts a strong and prevalent control on observed d-excess seasonality and overprints the effect of oceanic evaporation conditions. In mid-latitudes, the effect of oceanic evaporation conditions becomes stronger and seems dominant in the observed d-excess seasonality. However, the ultimate d-excess signals are produced after complex modulations by several reinforcing or competing processes, including prior distillations, moisture recycling, supersaturation in snow formation, and raindrop re-evaporation. Among these processes, substantial increases in the proportion of recycled moisture during the warm and dry season do not produce higher precipitation d-excess in mid-latitude continental interiors. We develop a simple seasonal water storage model to show that contributions of previously evaporated residual water storage and higher transpiration fractions may lead to relatively low d-excess in evapotranspiration fluxes during periods of enhanced continental moisture recycling. This study underscores the ubiquitous nonconservative behavior in d-excess throughout the water cycle, as opposed to using d-excess as a simple tracer for remote conditions at oceanic moisture sources.
Global biogeochemical cycles
|Type of Publication:||
A1 Journal article – refereed
|Field of Science:||
1172 Environmental sciences
This work was supported by the UMass Faculty Startup Fund to MJW. ZX was supported in part by the Fundamental Research Funds for the Central Universities (135112004). The USNIP program has been funded by the NSF awards (9413903, 9871262, 0923571) to JMW. JMW was supported in part by the UArctic Research Chairship.
© 2022. The Authors. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.