Precipitation Changes, Uncertainties, and Associated Impacts to the Arctic Environment
-
Upload
sean-francis -
Category
Documents
-
view
41 -
download
0
description
Transcript of Precipitation Changes, Uncertainties, and Associated Impacts to the Arctic Environment
![Page 1: Precipitation Changes, Uncertainties, and Associated Impacts to the Arctic Environment](https://reader035.fdocuments.net/reader035/viewer/2022062720/56813525550346895d9c8e65/html5/thumbnails/1.jpg)
Precipitation Changes, Uncertainties, and Associated
Impacts to the Arctic Environment
Michael Rawlins
Alexander Shiklomanov
Richard Lammers
Katelyn Dolan
Charles Vorosmarty
Arctic Research Consortium of the United States
2007 Annual Meeting and Arctic Forum
May 24, 2007
![Page 2: Precipitation Changes, Uncertainties, and Associated Impacts to the Arctic Environment](https://reader035.fdocuments.net/reader035/viewer/2022062720/56813525550346895d9c8e65/html5/thumbnails/2.jpg)
It is very likely that precipitation over the past century has
increased across the mid and high-latitudes of the Northern
Hemisphere---with the largest trends having come during
winter---and recent model simulations suggest that future
increases are likely to occur.
Summary Statement:
![Page 3: Precipitation Changes, Uncertainties, and Associated Impacts to the Arctic Environment](https://reader035.fdocuments.net/reader035/viewer/2022062720/56813525550346895d9c8e65/html5/thumbnails/3.jpg)
20th Century Precipitation Changes
![Page 4: Precipitation Changes, Uncertainties, and Associated Impacts to the Arctic Environment](https://reader035.fdocuments.net/reader035/viewer/2022062720/56813525550346895d9c8e65/html5/thumbnails/4.jpg)
“It is probable that there
was an increase in arctic
precipitation over the past
century”
Arctic Climate Impacts
Assessment, 2005
![Page 5: Precipitation Changes, Uncertainties, and Associated Impacts to the Arctic Environment](https://reader035.fdocuments.net/reader035/viewer/2022062720/56813525550346895d9c8e65/html5/thumbnails/5.jpg)
The largest increases have
occurred during winter
Arctic Climate Impacts
Assessment, 2005
![Page 6: Precipitation Changes, Uncertainties, and Associated Impacts to the Arctic Environment](https://reader035.fdocuments.net/reader035/viewer/2022062720/56813525550346895d9c8e65/html5/thumbnails/6.jpg)
• All 21 AR4 models have increasing trend in ensemble mean
• Only 4 have an ensemble run with a negative trend result
Kattsov et al., JGR, in press
![Page 7: Precipitation Changes, Uncertainties, and Associated Impacts to the Arctic Environment](https://reader035.fdocuments.net/reader035/viewer/2022062720/56813525550346895d9c8e65/html5/thumbnails/7.jpg)
Winter trends are similar to
annual means
Summer shows no systematic
changes
Kattsov et al., JGR, in press
![Page 8: Precipitation Changes, Uncertainties, and Associated Impacts to the Arctic Environment](https://reader035.fdocuments.net/reader035/viewer/2022062720/56813525550346895d9c8e65/html5/thumbnails/8.jpg)
Frequency of summer wet days and days with heavy rains
Sun and Groisman, 2000, Int. J. Climatol.
![Page 9: Precipitation Changes, Uncertainties, and Associated Impacts to the Arctic Environment](https://reader035.fdocuments.net/reader035/viewer/2022062720/56813525550346895d9c8e65/html5/thumbnails/9.jpg)
Trends in annual precipitation for the western part of the
former USSR (years: 1936-1997)
North of 60 N: Significant trend in TOTAL and HEAVY (90th percentile) P
South of 55 N: Significant trend in TOTAL, HEAVY and VERY HEAVY (99th) P
![Page 10: Precipitation Changes, Uncertainties, and Associated Impacts to the Arctic Environment](https://reader035.fdocuments.net/reader035/viewer/2022062720/56813525550346895d9c8e65/html5/thumbnails/10.jpg)
Key Uncertainties in Estimating Arctic Precipitation
• The sparse network of in situ observations
• The difficulty in obtaining estimates of solid precipitation in
windy environments
• Slow progress in exploiting remote sensing techniques for
measuring high-latitude precipitation
• Compounding effects of elevation on precipitation
Arctic Climate Impacts Assessment, 2005
![Page 11: Precipitation Changes, Uncertainties, and Associated Impacts to the Arctic Environment](https://reader035.fdocuments.net/reader035/viewer/2022062720/56813525550346895d9c8e65/html5/thumbnails/11.jpg)
Rawlins et al., 2006, GRL
Counterintuitive precipitation trends, relative to discharge trend, partially explained by gage density
change
![Page 12: Precipitation Changes, Uncertainties, and Associated Impacts to the Arctic Environment](https://reader035.fdocuments.net/reader035/viewer/2022062720/56813525550346895d9c8e65/html5/thumbnails/12.jpg)
Gauge undercatch is a significant problem, especially in winter
Yang et al., 2005, GRL
January Correction Factor July Correction Factor
![Page 13: Precipitation Changes, Uncertainties, and Associated Impacts to the Arctic Environment](https://reader035.fdocuments.net/reader035/viewer/2022062720/56813525550346895d9c8e65/html5/thumbnails/13.jpg)
Most General Circulation
Models (GCMs) tend to
overestimate precipitation...
http://igloo.atmos.uiuc.edu/IPCC/
![Page 14: Precipitation Changes, Uncertainties, and Associated Impacts to the Arctic Environment](https://reader035.fdocuments.net/reader035/viewer/2022062720/56813525550346895d9c8e65/html5/thumbnails/14.jpg)
Future Precipitation Changes
![Page 15: Precipitation Changes, Uncertainties, and Associated Impacts to the Arctic Environment](https://reader035.fdocuments.net/reader035/viewer/2022062720/56813525550346895d9c8e65/html5/thumbnails/15.jpg)
Precipitation increases (2000-2100) are projected to
be greatest during winter across high northern
latitudes
IPCC 4th Assessment, 2007
December-February June-August
![Page 16: Precipitation Changes, Uncertainties, and Associated Impacts to the Arctic Environment](https://reader035.fdocuments.net/reader035/viewer/2022062720/56813525550346895d9c8e65/html5/thumbnails/16.jpg)
• All model suggest future precipitation increases across region 60N –
pole
• Departures range between 5 to 15 cm (~ 10% to 30% of mean)
http://igloo.atmos.uiuc.edu/IPCC/
![Page 17: Precipitation Changes, Uncertainties, and Associated Impacts to the Arctic Environment](https://reader035.fdocuments.net/reader035/viewer/2022062720/56813525550346895d9c8e65/html5/thumbnails/17.jpg)
The models suggest that precipitation increases across the Arctic will far
exceed the global trends.
Kattsov et al., JGR, in press
![Page 18: Precipitation Changes, Uncertainties, and Associated Impacts to the Arctic Environment](https://reader035.fdocuments.net/reader035/viewer/2022062720/56813525550346895d9c8e65/html5/thumbnails/18.jpg)
Winter Cyclones in the NCAR CCSM3
• Increased cyclone-associated precipitation
• Increased atmospheric precipitable water
Percent Increase in Precipitable Water
Finnis et al., JGR, in press
*
*
*
** *
![Page 19: Precipitation Changes, Uncertainties, and Associated Impacts to the Arctic Environment](https://reader035.fdocuments.net/reader035/viewer/2022062720/56813525550346895d9c8e65/html5/thumbnails/19.jpg)
Magnitude of P-E changes (1950-2050) vary widely among models and are
significantly correlated with initial precipitation conditions
Holland et al., JGR, in press
![Page 20: Precipitation Changes, Uncertainties, and Associated Impacts to the Arctic Environment](https://reader035.fdocuments.net/reader035/viewer/2022062720/56813525550346895d9c8e65/html5/thumbnails/20.jpg)
Changes in Snowfall and Impact on
River Runoff
![Page 21: Precipitation Changes, Uncertainties, and Associated Impacts to the Arctic Environment](https://reader035.fdocuments.net/reader035/viewer/2022062720/56813525550346895d9c8e65/html5/thumbnails/21.jpg)
Discharge from the
major Russian rivers
has increased...
Peterson et al., 2002, Science
![Page 22: Precipitation Changes, Uncertainties, and Associated Impacts to the Arctic Environment](https://reader035.fdocuments.net/reader035/viewer/2022062720/56813525550346895d9c8e65/html5/thumbnails/22.jpg)
...but annual precipitation does not explain the increase
Berezovskaya et al., 2002, GRL
![Page 23: Precipitation Changes, Uncertainties, and Associated Impacts to the Arctic Environment](https://reader035.fdocuments.net/reader035/viewer/2022062720/56813525550346895d9c8e65/html5/thumbnails/23.jpg)
Discharge trends are greatest in the north
where permafrost is most extensive...
A. Shiklomanov, U. New Hampshire
![Page 24: Precipitation Changes, Uncertainties, and Associated Impacts to the Arctic Environment](https://reader035.fdocuments.net/reader035/viewer/2022062720/56813525550346895d9c8e65/html5/thumbnails/24.jpg)
...and where snowfall increases are also noted
Derived Snowfall Derived Rainfall
Rawlins et al., 2006, GRL
![Page 25: Precipitation Changes, Uncertainties, and Associated Impacts to the Arctic Environment](https://reader035.fdocuments.net/reader035/viewer/2022062720/56813525550346895d9c8e65/html5/thumbnails/25.jpg)
The snowfall trends are consistent, spatially,
with trends in observed runoff
![Page 26: Precipitation Changes, Uncertainties, and Associated Impacts to the Arctic Environment](https://reader035.fdocuments.net/reader035/viewer/2022062720/56813525550346895d9c8e65/html5/thumbnails/26.jpg)
Scenarios for future snowfall show both winners and losers
Rawlins et al., 2007, in prep.
![Page 27: Precipitation Changes, Uncertainties, and Associated Impacts to the Arctic Environment](https://reader035.fdocuments.net/reader035/viewer/2022062720/56813525550346895d9c8e65/html5/thumbnails/27.jpg)
Larger changes emerge for the more extreme A2 emissions scenario
Rawlins et al., 2007, in prep.
![Page 28: Precipitation Changes, Uncertainties, and Associated Impacts to the Arctic Environment](https://reader035.fdocuments.net/reader035/viewer/2022062720/56813525550346895d9c8e65/html5/thumbnails/28.jpg)
Summary
• In situ data show an increase in 20th century precipitation. Largest
increase in winter season.
• Positive snowfall trends are noted where increases in Eurasian
river discharge have occurred.
• Models depict future precipitation and P-E increases, but spread
is significant.
• Estimates of derived snowfall useful for regional water resource
assessments.