1. Table 1. Data for coastal stations in Greenland.

2. (1) Precipitation before bias correction g cm-2 yr-1.
(2) Precipitation after bias correction g cm-2 yr-1.
(3) Here, E is evaporation estimates, which were interpolated using Inverse Distance Weighting based on 5-km resolution ERA-40 values from 1958 to 2005 provided by Edward Hanna at the University of Sheffield, UK.
(4) Solid precipitation after bias correction g cm-2 yr-1.
(5) Accumulation g cm-2 yr-1.
(6) Data of 2000 and 2003 are not involved.
(7) SISIMIUT (average of 4230 and 4234).
(8) Average of ILLOQQORTOORMIUT and UUNARTEQ.
(9) Data of and are not involved.
(10) Data of ,1965 and1977 are not involved.
(11) Average of NERIUNAQ, QORNOQ and KAPSIGDLIT.

3. Uncorrected precipitation, g cm-2 yr-1
Bias corrected precipitation, g cm-2 yr-1
Figure 1. Precipitation for 20 coastal stations before versus after bias correction. The bias correction for the 20 stations averaged 47.3%. This compares well with the results of Yang et al.[1999], who reported corrections to the gauge-measured annual totals of 50-75% in the northern and 20-40% in the southern part of Greenland.

4. Solid precipitation, % Temperature, ºC
Figure 2. Relationship between temperature and solid precipitation. The original curve was published by Ohmura et al. [1999], who created the curve based on two datasets involving the individual synoptic observations from 17 Greenland stations, in which each precipitation event is characterized by the type of precipitation. In this study we digitalized the original curve and developed curve-fitting equations (equation (1)) to help divide precipitation into solid precipitation and liquid precipitation, as long as the mean air temperature is available for the corresponding period.

5. Equation (1). Curve-fitting equations to help divide precipitation into solid precipitation and liquid precipitation.

6. Table 2. PARCA new ice core data.
a Elevation meters above sea level.
b Annual accumulation g cm-2 yr-1.
r The point was used to replace another point used by Bales et al. [2001].

7. Figure 3. Data for kriging interpolation
Figure 3. Data for kriging interpolation. The data set involves 39 new ice core data developed by PARCA group, plus 250 ice core and snowpit data used by Bales et al. [2001] and 26 coastal accumulation estimates (20 points reported by Danish Meteorological Institute (DMI) and 6 points used by Ohmura et al. [1999]).

8. Cumulative percent of points
Number of years in record
Figure 4. Distribution of record lengths for point accumulation estimates using ice cores and snowpits. In the current analysis none of the estimates based on a single year’s measurement, which as estimates of a long-term mean have large uncertainty, were used.

9. Figure 5. Accumulation estimation map based on kriging
Figure 5. Accumulation estimation map based on kriging. Using solid precipitation minus evaporation (Ps - E) from coastal stations. Accumulation generally increases from northern Greenland to southern Greenland, and is higher in southern coastal areas. The average accumulation over Greenland is 29.0 g cm-2 yr-1 while the average accumulation over the ice sheet is 30.0 g cm-2 yr-1. Also shown for reference are the 2000 m and 3000 m elevation contours.

10. Figure 6. Accumulation map published by Bales et al. [2001].

11. Figure 7. Accumulation estimation standard error map based on kriging
Figure 7. Accumulation estimation standard error map based on kriging. Also shown for reference are the points used to develop the kriged surface. Here the uncertainty involves data uncertainty and algorithm uncertainty. The range of the prediction standard error is g cm-2 yr-1.

12. Figure 8. Difference between accumulation map in this research and that published by Bales et al. [2001]. Our new accumulation map indicates much lower accumulation in the southwest and much higher in the southeast, meaning that long term mass balance in both catchments is closer to steady state than previously estimated [Thomas et al., 2001]. Also shown are Greenland drainage basins, ice cores and snowpits data used in current research and that used in Bales et al. [2001]. Average accumulation in each basin was calculated and listed in Table 3. 

13. Table 3. Average accumulation by basin.
*Bales et al. [2001]. Both Ps-E and P-E contain ice cores and snowpits data. The only difference between the two approaches is the way of using meteorological coastal data to estimate accumulation over the Greenland ice sheet.

14. Table 4. Comparison of the interpolation results over the Greenland ice sheet from different data sources.
*Bales et al. [2001].

15. REFERENCES
Bales, R. C., J. R. McConnell, E. Mosley-Thompson, and B. Csatho, J. Grophys. Res., 106(D24), (2001).
Ohmura A., and N. Reeh, J. Glaciol., 37(125), (1991).
Ohmura, A., P. Calanca, M. Wild, and M. Anklin, Zeitschrift fur Gletscherkunde und Glazialgeologie, Universitatsverlag Wagner, Innsbruck, Band 35, Heft 1, 1-20 (1999).
Thomas, R., B. Csatho, C. Davis, C. Kim, W. Krabill, S Manizade, J. McConnell, and J. Sonntag, J. Geophys. Res., 106(D24), (2001).
Yang, D., S. Ishida, B.E. Goodison, T. Gunther, J. Geophys. Res., 105(D6), (1999).