The K-transect in west Greenland: Automatic weather station data (1993–2016)

Paul C J P Smeets,Peter Kuipers Munneke,Dirk Van As,Michiel R Van Den Broeke,Wim Boot,Hans Oerlemans,Henk Snellen,Carleen H Reijmer,Roderik S W Van De Wal

doi:10.1080/15230430.2017.1420954

Paul C J P Smeets, Peter Kuipers Munneke + Show 7 more

Open Access

https://doi.org/10.1080/15230430.2017.1420954

Copy DOI

Abstract

ABSTRACT We present twenty-three years (1993–2016) of automatic weather station (AWS) data, collected along the K-transect near Kangerlussuaq in west Greenland. The transect runs from east to west, roughly perpendicular to the ice sheet edge at about 67° N. The K-transect originated from the Greenland Ice Margin Experiments (GIMEX), held in the summers of 1990 and 1991. Until recently, surface mass balance and ice velocity measurements were performed at nine locations along the K-transect, of which four are equipped with AWS: two in the ablation zone at approximately 500 m and 1,000 m asl, one at the approximate equilibrium-line altitude (~1,500 m asl), and one in the lower accumulation zone (~1,850 m asl) at distances of 5, 38, 88, and 140 km from the ice edge, respectively. Here, we present an overview of the various AWS types and their data corrections, quality, and availability, including a preliminary trend analysis. Recent increases in temperature and radiation components are associated with the frequent occurrence of anti-cyclonic conditions in west Greenland, resulting in clear skies and relatively warm summers. Strong melt concurs with a decrease in winter accumulation, lowering the surface albedo of the ice sheet. The AWS situated at 1,500 m asl, the former equilibrium-line altitude (ELA), observed almost a doubling of the summertime net shortwave radiation since 2004; as a result, the ELA along the K-transect has been steadily increasing and is currently situated well above 1,700 m asl.

Highlights

Observations unambiguously show that the rate at which the Greenland Ice Sheet (GrIS) loses mass has increased since 1990 (Alley et al 2005; Rignot and Kanagaratnam 2006; Rignot et al 2011; Velicogna and Wahr 2006)
Twenty-three years (1993–2016) of automatic weather atation (AWS) and surface mass balance (SMB) data collected along the K-transect in west Greenland are presented
After data homogenization, which attempts to correct for various sensor errors and the use of different sensors and station types where necessary, we show that the K-transect data give useful information about climate and climate trends in this part of Greenland

Summary

Introduction

Observations unambiguously show that the rate at which the Greenland Ice Sheet (GrIS) loses mass has increased since 1990 (Alley et al 2005; Rignot and Kanagaratnam 2006; Rignot et al 2011; Velicogna and Wahr 2006). The surface energy balance (SEB), which determines melt, must be modeled correctly for projections of future GrIS mass loss to be accurate Doing this for the full GrIS requires the use of a regional atmospheric climate model that resolves the ice sheet climate and SEB at sufficiently high spatial resolution (van de Wal and Oerlemans 1994; Ettema et al 2009; Fettweis et al 2010; Gorter et al 2014; Noël et al 2016). These models must be evaluated using in situ climate and SEB observations from the ice sheet surface (Ettema et al 2010a, 2010b; Noël et al 2015) These observations are scarce: the operation of automatic weather stations (AWS) in the GrIS ablation zone is difficult, owing to the presence of crevasses, slush, large ice hummocks, and meltwater streams/lakes. This strongly limits the availability of long-term, reliable climate and SEB time series from the GrIS

Objectives

Findings

Conclusion