The fate of land evaporation – a global dataset

Andreas Link,Matthias Finkbeiner,Stephanie Eisner,Markus Berger,Ruud Van Der Ent

doi:10.5194/essd-12-1897-2020

Abstract

Abstract. Various studies investigated the fate of evaporation and the origin of precipitation. The more recent studies among them were often carried out with the help of numerical moisture tracking. Many research questions could be answered within this context, such as dependencies of atmospheric moisture transfers between different regions, impacts of land cover changes on the hydrological cycle, sustainability-related questions, and questions regarding the seasonal and interannual variability of precipitation. In order to facilitate future applications, global datasets on the fate of evaporation and the sources of precipitation are needed. Since most studies are on a regional level and focus more on the sources of precipitation, the goal of this study is to provide a readily available global dataset on the fate of evaporation for a fine-meshed grid of source and receptor cells. The dataset was created through a global run of the numerical moisture tracking model Water Accounting Model-2layers (WAM-2layers) and focused on the fate of land evaporation. The tracking was conducted on a 1.5∘×1.5∘ grid and was based on reanalysis data from the ERA-Interim database. Climatic input data were incorporated in 3- to 6-hourly time steps and represent the time period from 2001 to 2018. Atmospheric moisture was tracked forward in time and the geographical borders of the model were located at ±79.5∘ latitude. As a result of the model run, the annual, the monthly and the interannual average fate of evaporation were determined for 8684 land grid cells (all land cells except those located within Greenland and Antarctica) and provided via source–receptor matrices. The gained dataset was complemented via an aggregation to country and basin scales in order to highlight possible usages for areas of interest larger than grid cells. This resulted in data for 265 countries and 8223 basins. Finally, five types of source–receptor matrices for average moisture transfers were chosen to build the core of the dataset: land grid cell to grid cell, country to grid cell, basin to grid cell, country to country, basin to basin. The dataset is, to our knowledge, the first ready-to-download dataset providing the overall fate of evaporation for land cells of a global fine-meshed grid in monthly resolution. At the same time, information on the sources of precipitation can be extracted from it. It could be used for investigations into average annual, seasonal, and interannual sink and source regions of atmospheric moisture from land masses for most of the regions in the world and shows various application possibilities for studying interactions between people and water, such as land cover changes or human water consumption patterns. The dataset is accessible under https://doi.org/10.1594/PANGAEA.908705 (Link et al., 2019a) and comes along with example scripts for reading and plotting the data.

Highlights

Where does evaporated water go to, and where is the origin of precipitation? These questions have been addressed by more and more studies within the last few decades, as demonstrated in more detail below
In order to describe the fate of evaporation or the source of precipitation, the concept of atmospheric watersheds was developed in which the terms “evaporationshed” (Van der Ent and Savenije, 2013) and “precipitationshed” (Keys et al, 2012) were introduced
Relevant for largescale studies are numerical moisture tracking models, which were used in the majority of the more recent studies within this field (Dominguez et al, 2019; Van der Ent et al, 2013; Gimeno et al, 2012)

Summary

Introduction

Where does evaporated water go to, and where is the origin of precipitation? These questions have been addressed by more and more studies within the last few decades, as demonstrated in more detail below. Relevant for largescale studies are numerical moisture tracking models, which were used in the majority of the more recent studies within this field (Dominguez et al, 2019; Van der Ent et al, 2013; Gimeno et al, 2012). Those models show various application opportunities of which some of the main applications are listed and partly exemplified below: 1. Those models show various application opportunities of which some of the main applications are listed and partly exemplified below: 1. gaining increased knowledge on how regions of interest are dependent on the moisture supply from other regions (Bagley et al, 2012; Dirmeyer et al, 2009; Dominguez et al, 2016; Guo et al, 2019; Keune and Miralles, 2019; Keys et al, 2012, 2018; Salih et al, 2016; Staal et al, 2018; Zhao et al, 2016, 2019), 2. understanding land cover changes and their impacts on the supply of moisture to downwind beneficiaries (Bagley et al, 2012; Keys et al, 2012, 2018; Spracklen et al, 2012; Staal et al, 2018; Tuinenburg et al, 2012; Wang-Erlandsson et al, 2018; Wei et al, 2013, 2016), 3. applications within the context of sustainability and water footprinting (Berger et al, 2014, 2018), 4. understanding the seasonality of precipitation (Guo et al, 2019; Miralles et al, 2016; Zhang et al, 2017) and its interannual variability (Guo et al, 2019; Keys et al, 2018; Sodemann et al, 2008), 5. understanding precipitation changes and trends (Zhang et al, 2017, 2019), 6. investigations into impacts of climate change on the hydrological cycle (Bosilovich et al, 2005; Findell et al, 2019; Singh et al, 2016, 2017), 7. understanding extreme weather events such as droughts and floods (Dirmeyer and Brubaker, 1999; Drumond et al, 2019; Gangoiti et al, 2011; Gimeno et al, 2016; Herrera-Estrada et al, 2019; Nieto et al, 2019)

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Conclusion