Does GRACE see the terrestrial water cycle 'intensifying'?

Eicker, Annette, Forootan, Ehsan ORCID: https://orcid.org/0000-0003-3055-041X, Springer, Anne, Longuevergne, Laurent and Kusche, Jürgen 2016. Does GRACE see the terrestrial water cycle 'intensifying'? Journal of Geophysical Research: Atmospheres 121 (2) , pp. 733-745. 10.1002/2015JD023808

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Abstract

Several researchers have postulated that, under a changing climate due to anthropogenic forcing, an intensification of the water cycle is already under way. This is usually related to increases in hydrological fluxes as precipitation (P), evapotranspiration (E), and river discharge (R). It is under debate, however, whether such observed or reconstructed flux changes are real and on what scales. Large-scale increase or decrease of the flux deficit (P-E-R), i.e., flux changes that do not compensate, would lead to acceleration or deceleration of water storage anomaliespotentially visible in Gravity Recovery and Climate Experiment (GRACE) data. In agreement with earlier studies, we do find such accelerations in global maps of gridded GRACE water storage anomalies over 2003–2012. However, these have been generally associated with interannual and decadal climate variability.Yet we show that even after carefully isolating and removing the contribution of El Niño that partially masks long-term changes, using a new method, accelerationsofupto12mm/yr2 remaininregionssuchasAustralia,Turkey,andNorthernIndia.Werepeat our analysis with flux fields from two global atmospheric reanalyses that include land surface models (ERA-Interim and MERRA-Land). While agreeing well with GRACE on shorter time scales, they fall short in displaying long-term trends corresponding to GRACE accelerations. We hypothesize that this may be due totime-varyingbiasesinthereanalysisfluxesasnoticedinotherstudies.Weconcludethateventhoughits data record is short, GRACE provides new information that should be used to constrain future reanalyses towardabetterrepresentationoflong-termwatercycleevolution.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Earth and Environmental Sciences
Publisher:	American Geophysical Union (AGU)
ISSN:	2169-897X
Date of First Compliant Deposit:	6 March 2017
Date of Acceptance:	21 December 2015
Last Modified:	18 Nov 2023 06:25
URI:	https://orca.cardiff.ac.uk/id/eprint/92345

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