Using remotely sensed data from AIRS to estimate the vapor flux on the Greenland ice sheet: Comparisons with observations and a regional climate model

• Main Authors: Boisvert, Linette N., Lee, Jae N., Lenaerts, Jan T.M., Noël, Brice, van den Broeke, Michiel R., Nolin, Anne W.
• Other Authors: Sub Dynamics Meteorology, Marine and Atmospheric Research
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2017
• Subjects: AIRS; GC-Net; Greenland; RACMO; sublimation; surface mass balance; Geophysics; Oceanography; Forestry; Ecology; Aquatic Science; Water Science and Technology; Soil Science; Geochemistry and Petrology; Earth-Surface Processes; Atmospheric Science; Earth and Planetary Sciences (miscellaneous); Space and Planetary Science; Palaeontology; Ice Sheet
• Online Access: https://dspace.library.uu.nl/handle/1874/352451

Mass loss from the Greenland ice sheet (GrIS) in recent years has been dominated by runoff from surface melt. It is currently being studied extensively, while little interest has been given to the smallest component of surface mass balance (SMB): the vapor flux. Although poorly understood, it is not negligible and could potentially play a larger role in SMB in a warming climate where temperature, relative humidity, and precipitation changes remain uncertain. Here we present an innovative approach to estimate the vapor flux using the Atmospheric Infrared Sounder (AIRS) version 6 data and a modified vapor flux model (BMF13) over the GrIS between 2003 and 2014. One modification to the BMF13 model includes a new Multiangle Imaging SpectroRadiometer surface aerodynamic roughness product, which likely produces more accurate estimates of the drag coefficient on the ice sheet. When comparing AIRS data with GC-Net and Programme for Monitoring of the Greenland Ice Sheet automatic weather station observations of skin temperature, near-surface air temperature, and humidity, they agree within 2 K, 2.68 K, and 0.34 g kg−1. Largest differences occur in the ablation zone where there is significant subgrid heterogeneity. Overall, the average vapor flux from the GrIS between 2003 and 2014 was found to be 14.6 ± 3.6 Gt yr−1. No statistically significant trends were found during the data record. This data set is compared to the Regional Atmospheric Climate Model (RACMO2.3) vapor flux, and BMF13 produced smaller vapor fluxes in the summer (~0.05 Gt d−1) and slightly more deposition in the winter (~9.4 × 10−3 Gt d−1). Annually, differences between BMF13 and RACMO2.3 were only 30 ± 15%.