Figure 7. Monthly temperature from station observation, temperature
biases from default (DEF) and wetland scheme (WS) simulations, and the
cooling effect induced by the WS in the summer (May-August) for
three-year simulations.
In the summer of 2006, a record-breaking heatwave hit the major part of
the U.S. and Southern Canada. The extreme heat conditions can be
represented by the number of “hot days” during the summer, with the
daily maximum temperature exceeding the 90th percentile of the 30-year
climatology. We summed the number of hot days from May to August in 2006
from two simulations and the results are shown in Figure 8. Through
these four months, the hottest region is in the southeast of the domain
in Nebraska, Iowa, Kansas and Missouri – with more than 40 hot days –
while in the Northern Great Plains and Canadian Prairies, the hot days
are about 10~20 days. The WS simulation shows that
wetlands could effectively reduce the number of hot days by about 10
days in the entire domain. Two regions receive greater impacts from
wetlands, including southern Manitoba and the area between Nebraska and
Iowa. This result manifests the important role of wetlands in mitigating
climate change, especially in extreme heat events.