Scientific Theme: Advanced Modeling and Observing Systems

Scientific Theme: Regional Processes
Scientific Theme: REGIONAL PROCESSES
RP-01: Regional Hydrologic Cycles in Weather and Climate
PSD11: Water Cycle
RP-02: Surface/Atmosphere Exchange
PSD12: Air-Sea Interaction
RP-03: Regional Air Quality
CSD08: Regional Air Quality
GMD06: Baseline Air Quality
GSD02: Regional Air Quality Prediction
PSD13: Air Quality
RP-04: Intercontinental Transport and Chemical Transformation
CSD05: Tropospheric and Stratospheric Transport and Chemical Transformation
RP-05 Aerosol Chemistry and Climate Implications
CSD09: Aerosol Formation, Chemical Composition, and Radiative Properties
PSD11: Water Cycle
RP-01: Regional Hydrologic Cycles in Weather and Climate
GOAL:
Improve weather and climate predictions through an increased knowledge of regional and global water cycle
processes.
MILESTONE PSD11.1:
Plan and execute the 2007 HMT-West (Hydrometeorology Testbed) field campaign in the
northern California American River basin, located in the Sierra Nevada Mountains west of Lake
Tahoe and east of Sacramento. This effort will involve deployment of several instrument systems
utilized in HMT-West 2006 deployment in the American River Basin that will yield critical new
understanding of orographic influences on airflow and precipitation growth over the Sierra
Nevada mountains as well as streamflow response. CIRES investigators will be key participants
and contributors to this activity.
ACCOMPLISHMENTS FOR PSD11.1:
The second year of full-scale field operations for HMT in the American River Basin (HMT-West 2007) was
conducted from November 30, 2006 to March 22, 2007. The winter was drier than normal in the area, and only
seven intensive operating periods (IOPs) were conducted, compared to fourteen in the previous wetter-than-normal
winter. Not surprisingly, streamflow was also much reduced during HMT-West 2007 compared to HMT-West 2006.
However, two of the seven IOPs were very large storms; one dropped nine inches of rainfall (IOP 5) and the other
dropped three feet of snow at Blue Canyon (IOP 7). Concentrated arrays of unattended instruments, including wind
profilers, S-band precipitation profilers, various disdrometers, conventional and experimental precipitation and snow
gauges, soil moisture sensors, stream level gauges, and surface meteorological stations monitored atmospheric and
hydrologic conditions continuously for the entire four months. These observations were augmented during IOPs by
manned operations of the NSSL SMART-R gap-filling Doppler radar and serial radiosonde launches by local
students managed by ESRL PSD. Supplemental rawinsondes were released from Reno on three of the seven IOP‘s.
Unfortunately, staffing limitations at Oakland allowed supplemental rawinsonde releases during part of only one
IOP. Experimental, high-resolution (3 km) numerical weather-prediction models were run daily by ESRL GSD and
produced probabilistic forecasts of various precipitation amounts in the Basin. Forecasts, crew deployments, and
storm debriefings were discussed on daily conference calls among the NWS, ESRL, and NSSL participants of
HMT-West 2007.
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