1. Annual accumulation for Greenland updated using ice-core data developed during & analysis of daily coastal data
Roger Bales, UC Merced
Dayong Shen, UC Merced
Joe McConnell, Desert Research Institute
John Burkhart, Norwegian Institute for Air Research
Qinghua Guo, UC Merced

2. PARCA 2001 accumulation map
Mean: 30 g cm2 a-1
South: g cm2 a-1
Northeast: g cm2 a-1
West: g cm2 a-1
Uncertainties
High-accumulation gradients in south
Coastal up to dry snow
Bales et al., JGR 2001

3. Coastal weather station data
2001 map
17 locations, monthly data
Consolidated data from Ohmura’s 1999 analysis of 36 locations
Only 8 stations with data past 1990, 5 more with records ending in 1980’s
Wind corrections for undercatch in rain gages based on monthly averages
Current analysis
22 DMI stations, daily data
13 with data past 2000
Most with data into 1980’s
Wind corrections for undercatch in rain gages based on daily averages

4. Trends at 8 stations co-located between Ohmura, 1999 & current analysis
6 sites: +2.6 mm/yr

5. Offset at 8 stations co-located between Ohmura, 1999 & current analysis

6. Bias corrections

7. Data used in kriging 257 ice sheet points from Bales, 2001
39 new ice cores
20 new coastal stations
6 coastal stations from Ohmura, 1999

8. Distribution of record lengths on ice sheet
Cumulative percent
Years in record
Mean about 10 yr
Replaced single-year estimates

9. PS-E
Current minus 2001 map

10. PS-E
PC-E

11. Total rather than solid precipitation as better estimate of accumulation in wet snow region?

12. Basin-by-basin comparison
Current minus 2001 map
Basin-by-basin comparison
Basin
Map values
Pc-E
Ps-E
P-E* 1
38.4
37.7 2
39.0
40.0 3
53.5
42.4
49.1 4
65.2
60.7
52.0 5
56.5
55.2
49.7 6
35.6
34.3 7
18.2
18.0 8
13.6
13.3
13.9 9
12.3 10
15.3
15.2
15.4 11
28.0
27.2
27.4 12
32.7
32.0
32.5

13. Summary of accumulation
Area
Accumulation, g cm-2 yr-1
Pc - E
Ps - E
P-E*
Greenland
36.5
29.0
29.8
Ice sheet
34.6
30.0
30.4
E ≥ 2000 m
31.8
29.9
1.7
1.1 –
Standard error
Standard error: from variance estimates plus covariance terms