Climate drivers of Interior Alaska wildland fire

Abstract

This study focused on the climate drivers of wildfire in Interior Alaska that occurred in summer season, JJA, during periods in 1994 to 2017. Analysis results presented in this paper provide identify links between meteorological variables and area burned, in the context of spatial and temporal variability at the PSA level. Warmer temperatures caused higher chance of wildland fires as in summer 2004 (26797 km2) where the temperature reached the highest levels compared to all years of study. In addition, this study has shown that temperatures have the same seasonal cycle in all PSAs level; where the temperature increase begins in June, peaks in July and then gradually decline, consistent with the fire season. Although precipitation limits the increase in forest fires, the accompanying lightning increases the chance fires which gives precipitation a double role in influencing the risk of fire. This can be seen clearly in both Upper Yukon valley (AK02) and Tanana Zone South (AK03S) where the largest number of lightning strikes over Interior Alaska occur (17000 and 11000 strikes, respectively). In addition, these two PSAs have the greatest area burned (1441.2 and 1112.4 km2).There is an upward trend in both temperature and precipitation in all months especially in May and September which indicates a decline in the snow season and an increase in the length of the fire season. A similar pattern was documented between PSAs in eastern versus western Alaska. Eastern PSAs receive the highest amount of precipitation in July, (AK01W , AK01E, AK02, AK03N, AK03S) , and western PSAs in August, (AK04, AK05, AK07). The years 2004, 2015, 2005 and 2009 display the largest values for area burned with extremely warm and dry condition especially in 2004 with approximately 26797 km2 (6.6 m acres).