North American Water Project (NAWP, formerly TRACE)

North American Water Project (NAWP, formerly TRACE) •  NAWP will establish the scien>fic basis, observa>ons and modeling approaches required to manage water security and sustainability through climate and environmental change uncertain>es. This will require an interdisciplinary integra>on of North American hydroclimate observa>on and predic>on resources that transcends scales and enables procedures and analy>c tools to adapt to change. CHALLENGES: •  Adapta&on: Developing a scien>fic basis and tools to adapt to climate and environmental change. •  Benchmarking: Understanding the sensi>vity of the water cycle to change. •  Science informing decisions: Developing the capacity for science-­‐informed decisions related to climate and environmental change. Reanalyses in the Na>onal Climate Assessment MERRA summer>me precipita>on compares well with CPC over most of the US, especially NW but rather poor in the MW US. What controls the quality of the MERRA precipita>on? •  While Reanalyses assimilate observa>ons, many essen>al climate variables are derived from the background model forecast, with associated errors and uncertain>es Regional Precipita>on NW JJA Precip Anomalies (mm day-­‐1)
•  All reanalyses agree well in NW •  In MW 1.2
0.8
0.4
0.0
-­‐0.4
1979
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-­‐0.8
Gauge
MERRA
Interim
CFSR
MW JJA Precip Anomalies (mm day-­‐1)
1979
1980
1981
1982
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2.0
1.5
1.0
0.5
0.0
-­‐0.5
-­‐1.0
-­‐1.5
Gauge
MERRA
Interim
CFSR
–  MERRA underes>mates anomaly magnitude –  CFSR completely misses some anomalies –  Interim has a persistent trend ENSO Connec>on Observed JJA precip shows a correla>on to MAM ENSO34 in the NW, not in MW. Reanalyses agree with the NW correla>on, but also have some correla>on to ENSO34 in MW and SE. This suggests the large-­‐scale circula>on influence of ENSO persists for NW, but that the local coupling in the reanalyses is insufficient to represent reality. Summary •  Regarding Reanalyses in NCA: Some regions may be beZer represented than others in seasonal variability, but depends on variable •  For hydrology development predic>on, the local coupling, especially in MW and SE, could be an area where improved precipita>on predic>on could greatly affect the reanalyses results. •  There are many similari>es among the reanalyses; collec>vely, these could be exploited to quan>ta>vely assess the uncertainty •  Report, including evalua>on of air temperature: hZps://gmao.gsfc.nasa.gov/projects/NCA/ Backup slides Why MAM NINO34? NW JJA Pr Correlation To Seasonal ENSO34
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0.5
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JAS ASO SON OND NDJ DJF JFM FMA MAM AMJ MJJ JJA
CPC
MERRA
Interim
CFSR
JJA PR Correlation to MAM ENSO34
0.60
0.50
0.40
0.30
0.20
0.10
0.00
-0.10
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SE
MW
GP
SGP
NGP
NW
-0.20
-0.30
-0.40
Gauge
MERRA
Interim
CSFR
SW
US
•  In NW, reanalyses track CPC gauge obs with higher correla>on to ENSO in MAM •  In reanalyses (especially MERRA), this correla>on seems more wide spread than it should be