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The 2019 melt season over Greenland as simulated by MARv3.9

7-day forecast of 
the 2019 Greenland ice sheet SMB 
simulated by MARv3.9 forced by GFS

 (automatic updated every day around 8h TU)


Fig 0: Time series of the anomaly of cumulated Greenland ice sheet (GrIS) Surface Mass Balance (SMB) in GT simulated by the regional climate model MAR (version 3.9.6, run at a resolution of 20km) forced by the NCEP-NCARv1 reanalysis (1979-Mar 2019) and by the Global Forecast System (GFS) model (May 2019-the today's date +7 days in forecast mode). The gray shading area represents the 1981-2010 standard deviation around the 1981-2010 average. This plot can be put in parallel with the current state of the Arctic sea ice extent.

The daily numbers of this figure are available in ASCII here. (day, SMB of 2019 in GT/day, SMB of 2012, climatological mean over 1980-2010, standard deviation).


Fig 1: a) Time series of the cumulated Greenland ice sheet (GrIS) Surface Mass Balance (SMB) in GT simulated by the regional climate model MAR (version 3.9.6, run at a resolution of 20km) forced by the NCEP-NCARv1 reanalysis (1979-Mar 2019) and by the Global Forecast System (GFS) model (May 2019-the today's date +7 days in forecast mode) since 1 Sep 2011 (in green), and 1 Sep 2018 (in red). The 1981-2010 mean simulated by MARv3.9 forced by NCEP1 is also plotted in black. The 0-24h forecast of each day from the GFS run of 00hTU has been used to build the time series from the end of NCEP1 (March 2019) to now. Finally, the gray shading area represents the standard deviation around the 1981-2010 average (in black). b) Same as a) but for the daily SMB in GT/day.  The absolute maximum/minimum SMB rate of each day is plotted in blue. c) Daily mean GrIS near-surface temperature (TAS) simulated by MAR. The absolute maximum temperature of each day is plotted in blue. d) Time series of the North Atlantic Oscillation (NAO) index from Climate Prediction Center (CPC).

 


Fig 2a: Left) Cumulated SMB (in mm) from the 1 Sep 2017 to the today's date. Right) Same as Left) but in respect to the 1981-2010 NCEP1 forced average from the 1 Sep to the today's date. The anomalies lower than the 1981-2010 interannual variability are hatched.

 

 


Fig 2b: Same as Fig 2a but for snowfall.

 

 

Fig 2c: Same as Fig 2a but for run-off.

 


Fig 3: Time series of a) the daily mean GrIS Run-off (in GT/day), b) production of meltwater (in GT/day), c) daily mean GrIS incomming long/shortwave radiation (in W/m²)), d) bare ice extent (i.e. area where the surface density is > 900 kg/m^3 in % of the ice sheet surface) and e) daily mean GrIS surface albedo simulated by MARv3.9 forced by NCEP1 (1981-2019).

 
 
 
Fig 4: Left) Number of melt days ( (i.e. when the daily meltwater production > 5 mmWE/day) from the 1 May 2019 to the today's date. Right) Same as Left) but in respect to the 1981-2010 average from 1 May to 31 Aug.
 
 
Fig 5: Left) Melt extent as derived from satellite data (Credit: NSIDC/Thomas Mote). Right) Same as a) but as simulated by MARv3.9 forced by NCEP1 and forecasted forced by GFS. Daily meltwater production > 5 mmWE/day is used here as melt threshold in MARv3.9. This melt threshold has been chosen independently of the NSIDC data and mainly explains why both estimations do not generally compare.
 
 
 
Fig 6: Greenland bloking index (GBI) from NCEP-NCARv1 in red and from the Global Forecast System (GFS) based forcasting in dashed red. According to Hanna et al. (2013), the GBI is defined as the 500hPa geopotential height (Z500) area averaged over 60-80°N, 280-340°E.  
 
 
 
Fig 7: Idem as Fig. 6 but for 700hPa temperature (T700) averaged over 60-80°N, 280-340°E.  
 
 
 
Fig 8: Left) Anomaly of surface albedo in respect to the 1981-2010 average over the same day (today's date). Righ) Anomaly of the JJA mean surface albedo in respect to the 1981-2010 average from 1 May to the today's date. 
 
 
Fig 9: Same as Fig. 8 but for the near-surface temperature (~2m) as simulated by MARv3.9 forced by NCEP1. 
 
 
Fig 10: Same as Fig. 9 but for the incoming shortwave radiation (in W/m²) as simulated by MARv3.9 forced by NCEP1. 
 
 
Interesting links:
 

(c) Xavier FettweisUniversity of Liège (ULiège), Belgium

 

These forecasts are only provided for information in the aim of following the 2019 melting season over Greenland in real time; ULiège can not be held responsible for any use beyond this scope.