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[ACG39-04] Recent Fire Trends in the Arctic Region under Climate Change
Keywords:hotspot, climate change, warm air mass, westerlies, meandering
Recent studies1-4have revealed the weather conditions for large-scale fires in the Arctic. As the westerlies meandered and the high-pressure system developed at upper air, fires were activated under the temperate (cTe) moved from the south. This report analyzes recent fire activity in the Arctic region (Northern Hemisphere (> 50 N, 0-180 E & W) north of latitude 50 N). The number of hotspots (HS) in the summer (JJA) 19 years (2002-2020) detected by MODIS (Moderate Resolution Imaging Spectroradiometer) was about 3.98 million, and the Arctic region was divided into 288 grid cells (cell size: 2.5 N, 10 E & W). The annual average fire density of each grid (Number of hotspots (HSs): 103km-2year-1) was calculated to identify active fire areas in the Arctic.
Based on the analysis results, we identified active fire areas and examined the relationship between climate change and fire. Figure 1 shows the distribution of the annual average fire density. Active fire areas in the Arctic region were found from Central Siberia to western Canada, where 84% of all HSs were detected. In this report, the results of analysis of fire activity of the entire Arctic region and three major research areas with particularly active fire activity (1. Krasnoyarsk (57.5-65 N, 90-120 E), 2. N. Sakha (62.5-70 N, 120-150 E), and 3. Alaska (62.5-70 N, 130-160 W)) were reported.
Major analysis results:
1. The very active fires in the Krasnoyarsk area occurred on July 23, 2019, under the presence of warm air masses (cTe = 290 K) moved from south related to the westerly meandering and the development of high pressure at upper air.
2. The average number of fires (HS) in the Arctic region (> 50 N) was about 210,000 per year, and the number of fires north of latitude 60 degrees north was about 110,000. HS of the largest fire year, 2012, reached about 370,000.
3. In 2019 and 2020, fires in north latitude 60-70 degrees were active, with about 200,000 and 180,000 annually.
4. The largest fire year in the Krasnoyarsk area (1. Krasnoyarsk in Figure 1) was 2019, with approximately 130,000 HS, about 4.3 times the average.
5. The number of fires (HS) in northern Sakha was remarkable, about 65,000 in 2019 and about 80,000 in 2020, and were 3-4 times the average.
6. The average fire location in northern Sakha for 19 years was 65.2 N. The total number of fires in 2019 was about 66,000, and their average fire location was 67.2 N and it was within the Arctic Circle.
7. The number of HSs in Alaska was about 110,000 in 2004 and about 60,000 in 2005.
8. Alaska's average fire location for 19 years was 65.3 N. The highest average fire position was 66.4 degrees.
9. The weather conditions during the active fire period in the three major research areas were westerly meandering, formation of an anticyclone system, and northward movement of the warm air masses from the south. It was similar to the results of recent studies1-4.
10. The recent fire activity described above may indicate the impact of climate change on Arctic fires and is one piece of evidence of the impact of climate change.
References:
1. H. Hayasaka, H. L. Tanaka, P. A. Bieniek, Synoptic-scale fire weather conditions in Alaska, Polar Science, 10-3, 217-226, 2016.
2. H. Hayasaka, K. Yamazaki, and D. Naito, Weather Conditions and Warm Air Masses in Southern Sakha During Active Forest Fire Periods, J. Disaster Res., 14-4, 641-648, 2019.
3. H. Hayasaka, K. Yamazaki, and D. Naito, Weather Conditions and Warm Air Masses during Active Fire-periods in Boreal Forests, Polar Science, 22, 1-8, Article 100472, 2019.
4. H. Hayasaka, G. V. Sokolova , A. Ostroukhov and D. Naito, Classification of Active Fires and Weather Conditions in the Lower Amur River Basin, Remote Sens. 12(19), 3204, 2020.
Based on the analysis results, we identified active fire areas and examined the relationship between climate change and fire. Figure 1 shows the distribution of the annual average fire density. Active fire areas in the Arctic region were found from Central Siberia to western Canada, where 84% of all HSs were detected. In this report, the results of analysis of fire activity of the entire Arctic region and three major research areas with particularly active fire activity (1. Krasnoyarsk (57.5-65 N, 90-120 E), 2. N. Sakha (62.5-70 N, 120-150 E), and 3. Alaska (62.5-70 N, 130-160 W)) were reported.
Major analysis results:
1. The very active fires in the Krasnoyarsk area occurred on July 23, 2019, under the presence of warm air masses (cTe = 290 K) moved from south related to the westerly meandering and the development of high pressure at upper air.
2. The average number of fires (HS) in the Arctic region (> 50 N) was about 210,000 per year, and the number of fires north of latitude 60 degrees north was about 110,000. HS of the largest fire year, 2012, reached about 370,000.
3. In 2019 and 2020, fires in north latitude 60-70 degrees were active, with about 200,000 and 180,000 annually.
4. The largest fire year in the Krasnoyarsk area (1. Krasnoyarsk in Figure 1) was 2019, with approximately 130,000 HS, about 4.3 times the average.
5. The number of fires (HS) in northern Sakha was remarkable, about 65,000 in 2019 and about 80,000 in 2020, and were 3-4 times the average.
6. The average fire location in northern Sakha for 19 years was 65.2 N. The total number of fires in 2019 was about 66,000, and their average fire location was 67.2 N and it was within the Arctic Circle.
7. The number of HSs in Alaska was about 110,000 in 2004 and about 60,000 in 2005.
8. Alaska's average fire location for 19 years was 65.3 N. The highest average fire position was 66.4 degrees.
9. The weather conditions during the active fire period in the three major research areas were westerly meandering, formation of an anticyclone system, and northward movement of the warm air masses from the south. It was similar to the results of recent studies1-4.
10. The recent fire activity described above may indicate the impact of climate change on Arctic fires and is one piece of evidence of the impact of climate change.
References:
1. H. Hayasaka, H. L. Tanaka, P. A. Bieniek, Synoptic-scale fire weather conditions in Alaska, Polar Science, 10-3, 217-226, 2016.
2. H. Hayasaka, K. Yamazaki, and D. Naito, Weather Conditions and Warm Air Masses in Southern Sakha During Active Forest Fire Periods, J. Disaster Res., 14-4, 641-648, 2019.
3. H. Hayasaka, K. Yamazaki, and D. Naito, Weather Conditions and Warm Air Masses during Active Fire-periods in Boreal Forests, Polar Science, 22, 1-8, Article 100472, 2019.
4. H. Hayasaka, G. V. Sokolova , A. Ostroukhov and D. Naito, Classification of Active Fires and Weather Conditions in the Lower Amur River Basin, Remote Sens. 12(19), 3204, 2020.