Problems with the station network

There is still uncertainty regarding even mean precipitation totals in the Arctic. The basic problems were articulated in Chapter 2. To reiterate: (1) there is significant gauge undercatch of solid precipitation for which there are only imperfect adjustment procedures, the problem being compounded by the variety of gauge types and reporting practices used by different countries and by a switch to automated stations for some locations in Canada; (2) while the station network has always been sparse, it has further declined since about 1990. Furthermore, there have been long delays in posting station updates in readily available archives. Figure 6.1 highlights the large size of bias

Figure 6.1 Monthly precipitation for the central Arctic Ocean based on data from the Russian North Pole manned camps with daily bias adjustments. Raw precipitation totals are shown along with the adjustments for winds and neglect of trace amounts. Adjusted precipitation is represented by the total length of the bars (from Yang, 1999, by permission of AGU).

Figure 6.1 Monthly precipitation for the central Arctic Ocean based on data from the Russian North Pole manned camps with daily bias adjustments. Raw precipitation totals are shown along with the adjustments for winds and neglect of trace amounts. Adjusted precipitation is represented by the total length of the bars (from Yang, 1999, by permission of AGU).

Figure 6.2 Distribution of precipitation measuring stations north of 40° N with at least ten years of records for the period 1960-89, based on blending various data sets (by the authors).

adjustments, using as an example data from the NP drifting stations. To highlight the network problems, Figure 6.2 shows the distribution of land stations north of 40° N with at least ten years of data. Observations over northern Canada and Siberia are especially scanty. There is a growing network of observations over central Greenland, but these are from automated stations for which data quality is open to question. The situation is even worse over the central Arctic Ocean, where the NP stations provided spotty coverage from 1950 through 1991. At present there is no systematic observing program for precipitation in this area.

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