A 915-MHz wind profiler, a GPS receiver, and surface meteorological sites in and near California’s northern Central Valley (CV) provide the observational anchor for a case study on 23–25 October 2010. The study highlights key orographic influences on precipitation distributions and intensities across northern California during a landfalling atmospheric river (AR) and an associated Sierra barrier jet (SBJ). A detailed wind profiler/GPS analysis documents an intense AR overriding a shallow SBJ at ~750 m MSL, resulting in record early season precipitation. The SBJ diverts shallow, pre-cold-frontal, incoming water vapor within the AR poleward from the San Francisco Bay gap to the northern CV. The SBJ ultimately decays following the passage of the AR and trailing polar cold front aloft. A statistical analysis of orographic forcing reveals that both the AR and SBJ are crucial factors in determining the amount and spatial distribution of precipitation in the northern Sierra Nevada and in the Shasta–Trinity region at the northern terminus of the CV. As the AR and SBJ flow ascends the steep and tall terrain of the northern Sierra and Shasta–Trinity region, respectively, the precipitation becomes enhanced. Vertical profiles of the linear correlation coefficient quantify the orographic linkage between hourly upslope water vapor flux profiles and hourly rain rate. The altitude of maximum correlation (i.e., orographic controlling layer) is lower for the shallow SBJ than for the deeper AR (i.e., 0.90 versus 1.15 km MSL, respectively). This case study expands the understanding of orographic precipitation enhancement from coastal California to its interior. It also quantifies the connection between dry antecedent soils and reduced flood potential.
The Regional Influence of an Intense Sierra Barrier Jet and Landfalling Atmospheric River on Orographic Precipitation in Northern California: A Case Study
Authors:
Paul J. NeimanAffiliationsPhysical Sciences Division, NOAA/Earth System Research Laboratory, Boulder, Colorado F. Martin RalphAffiliations
Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California Benjamin J. MooreAffiliations
NOAA/ESRL, and Cooperative Institute for Research in the Environmental Sciences, Boulder, Colorado, and Department of Atmospheric and Environmental Sciences, University at Albany, State University of New York, Albany, New York Robert J. ZamoraAffiliations
Physical Sciences Division, NOAA/ESRL, Boulder, Colorado
Received: 7 November 2013
Final Form: 27 February 2014
Published Online: 30 July 2014
August 2014
Share this Article
Featured Collections
Mountain Terrain Atmospheric Modeling and Observations (MATERHORN) -BAMS, JAMC,MWR, WAF
LatMix -BAMS, JPO, JTECH
PANDOWAE -MWR, JAS, WAF, JTECH
Most Read JHM Articles
(past 12 months)
. |
Liu
March 2016, Vol. 17, No. 3
|
. |
Sospedra-Alfonso et al.
September 2016, Vol. 17, No. 9
|
. |
Duerinck et al.
June 2016, Vol. 17, No. 6
|
. |
Arnault et al.
May 2016, Vol. 17, No. 5
|
. |
Cattani et al.
October 2016, Vol. 17, No. 10
|
. |
Dirmeyer et al.
April 2016, Vol. 17, No. 4
|
Most Cited (past 12 months)
-
1. The TRMM Multisatellite Precipitation Analysis (TMPA): Quasi-Global, Multiyear, Combined-Sensor Precipitation Estimates at Fine ScalesHuffman et al.February 2007, Vol. 8, No. 1 -
2. The Version-2 Global Precipitation Climatology Project (GPCP) Monthly Precipitation Analysis (1979–Present)Adler et al.December 2003, Vol. 4, No. 6 -
3. A Global Dataset of Palmer Drought Severity Index for 1870–2002: Relationship with Soil Moisture and Effects of Surface WarmingDai et al.December 2004, Vol. 5, No. 6 -
4. CMORPH: A Method that Produces Global Precipitation Estimates from Passive Microwave and Infrared Data at High Spatial and Temporal ResolutionJoyce et al.June 2004, Vol. 5, No. 3 -
5. Global Precipitation at One-Degree Daily Resolution from Multisatellite ObservationsHuffman et al.February 2001, Vol. 2, No. 1 -
6. Creation of the WATCH Forcing Data and Its Use to Assess Global and Regional Reference Crop Evaporation over Land during the Twentieth CenturyWeedon et al.October 2011, Vol. 12, No. 5