Comparing Maps of Mean Monthly Surface Temperature and Precipitation for Alaska and Adjacent Areas of Canada Produced by Two Different Methods

Abstract

ABSTRACT. Maps of mean monthly surface temperature and precipitation for Alaska and adjacent areas of Canada, produced by Oregon State University's Spatial Climate Analysis Service (SCAS) and the Alaska Geospatial Data Clearinghouse (AGDC), were analyzed. Because both sets of maps are generally available and in use by the community, there is a need to document differences between the processes and input data sets used by the two groups to produce their respective set of maps and to identify similarities and differences between the two sets of maps and possible reasons for the differences. These differences do not affect the observed large-scale patterns of seasonal and annual variability. Alaska is divided into interior and coastal zones, with consistent but different variability, separated by a transition region. The transition region has high interannual variability but low long-term mean variability. Both data sets support the four major ecosystems and ecosystem transition zone identified in our earlier work. Differences between the two sets of maps do occur, however, on the regional scale; they reflect differences in physiographic domains and in the treatment of these domains by the two groups (AGDC, SCAS). These differences also provide guidance for an improved observational network for Alaska. On the basis of validation with independent in situ data, we conclude that the data set produced by SCAS provides the best spatial coverage of Alaskan long-term mean monthly surface temperature and precipitation currently available.

Inconsistency in precipitation measurements across the Alaska–Yukon border

“…This result is similar to other studies (Serreze and Hurst, 2000;Simpson et al, 2005). After the bias corrections, precipitation patterns across the border changed, i.e.…”

“…higher precipitation in Barter than Komakuk, or, in other words, an inverted gradient across the borderline. Over the central region, the measured mean annual precipitation is slightly higher in Yukon than Alaska, which is also consistent with Simpson et al (2002Simpson et al ( , 2005. Our results suggest that the gradient between the central pair of stations becomes smaller after the bias correction.…”

“…slightly higher P in Yukon relative to Alaska. This result is consistent with other studies (Simpson et al, 2002(Simpson et al, , 2005. The corrected data, on the other hand, suggest a smaller gradient (1 mm) across the border (Fig.…”

“…This is an important issue, since most regional precipitation data and products have been compiled and derived from the combination of various data sources, assuming these data and observations were compatible across the borders and among the national observational networks. Simpson et al (2005) studied temperature and precipitation distributions over the state of Alaska (AK) and west Yukon (YK), and documented precipitation increase from north to south. They also report differences in mean monthly precipitation across the Alaska-Yukon border, i.e.…”

Past and projected future changes in moisture conditions in the Canadian boreal forest

“…The approach has been subjected to rigorous testing to examine the predictive accuracy of the historical surfaces (e.g., Price et al 2000;Simpson et al 2005;McKenney et al 2006aMcKenney et al ,b, 2013. It has been established that the magnitude of errors at "withheld" climate stations in areas where such stations are sparsely distributed is generally about ±1.0°C to 1.5°C for monthly mean daily minimum and maximum temperatures and ±20% to 40% for precipitation.…”