Compatibility evaluation of national precipitation gage measurements

Compatibility of precipitation measurements of various national gages commo nly used in the Northern hemisphere countries has been evaluated, based on the gage intercomparison data collected at 10 stations during the World Met eorological Organization (WMO) Solid Precipitation Measurement Intercompari son Project. Little difference (less than 5%) is found between national rai nfall data, but a significant discrepancy (up to 110%) exists between natio nal snowfall records. This difference is not constant and it varies with wi nd speed and temperature. It is certain that use of different precipitation Sages in neighboring countries has introduced a significant discontinuity into precipitation records, particularly in cold and windy regions. Strong linear relations among daily national gage measurements have been defined f or several national gages commonly used in the Northern hemisphere. These l inear relations provide a useful technique to adjust gage records when wind speed and temperature data are not available. The linear relations have be en tested at selected WMO intercomparison stations, and good agreements of the adjusted amounts to other gage measurements are obtained at most of the test sites, indicating that the linear relations perform reasonably well a t the selected WMO sites. Use of the proposed adjustment procedure will red uce inconsistency between precipitation measurements of national gages.