Improving Observations of Coastal Storms

Allen White, NOAA/ESRL

Boulder, CO

With key contributions from Mike Dettinger (Scripps) and Dan Gottas, Seth Gutman, Paul Neiman, Marty Ralph,

Tim Schneider, and Gary Wick (ESRL)

Purpose and Outline

Purpose: To describe recent advances in observational research that have been developed to improve the detection and monitoring of key atmospheric phenomena associated with winter storms impacting California.

Outline• Part I: A new water vapor flux tool for monitoring

atmospheric rivers over land• Part II: CA DWR EFREP Program – Providing an HMT

legacy for California• Part III: UAS and the Pacific Testbed

Part IA new water vapor flux tool for monitoring

atmospheric rivers over land

•SSM/I satellite image of integrated water vapor (IWV) at 18UTC 16-Feb-04: AR landfall in N CA

•~250 mm rain in 2 days

•Stream gauge rankings for 17- Feb-04 show regional extent of high streamflow covering roughly 500 km of coast

•All flood events on the Russian River (in N CA) in last 10 years tied to land-falling ARs

atmosphericriver

• Heavy cool-season rain & flood events along the U.S. West Coast are orographically driven and occur most often when narrow warm-sector corridors of strong water-vapor transport (i.e., atmospheric rivers – ARs) intersect the coastal mountains (e.g., Ralph et al. 2006 in GRL; Neiman et al. 2008 in JHM).

Global reanalysis IVT (kg s-1 m-1): 16-Feb-04

IVT (kg s-1 m-1)

• Flood-prone Russian River Basin northwest of San Francisco: 2000/01, 2003/04, 2004/05, 2005/06

• Analyses for when the following observing systems were simultaneously operating – (a) Bodega Bay (BBY): GPS-IWV unit, 915-MHz wind profiler, rain gauge (b) Cazadero (CZD): rain gauge

• Total rainfall: CZD = 4217 mm, BBY = 2016 mm

• 9548 hourly data points

Upslope flow:orthogonal tothe axis of thecoastal mtns

30 km

Neiman et al. (2008), Water ManagementNeiman et al. (2002), MWR

Developed real-time monitoring of vapor transports to assess the orographicforcing, based on published research using wind profilers,

as well as GPS receivers that measure IWV

Component of the flow in the orographic controlling layer directed from 230°,i.e., orthogonal to the axis of the coastal mtns

All data points

Any rain:>0 m/s; >1 cm

Rain >5 mm/h:>6 m/s; >1.5 cm

Rain >10 mm/h:>12.5 m/s; >2 cm

Atmospheric river quadrant:Strongest IWV fluxes(i.e., U1km x IWV)* yieldheaviest rains

*Nearly 2/3 of tropospheric water vapor is in the lowest 2 km MSL.Hence, to first order, the IWV flux provides a close estimate

of the low-level water-vapor transport into the coastal mountains.

Bodega Bay (BBY; 12 m MSL)Piedras Blancas (PPB; 11 m MSL)Goleta (GLA; 3 m MSL)

Prototype WV flux tool tested at 3 couplets during NOAA’s HMT-2008

L

BBY/CZD

PPB/TPK

GLA/SMC

0030Z 5-Jan-08: Intense western U.S. storm

Coast (profiler, GPS, rain gauge):

Cazadero (CZD; 475 m MSL)Three Peaks (TPK; 1021 m MSL)San Marcos Pass (SMC; 701 m MSL)

Mountains (rain gauge):North:Central:South:

Couplet

land-fallingatmospheric river

The top of three panels of the forecast tooldisplays hourly wind profiles and snow levels

Current time

Altitudein km

Altitudein kft

Observed winds: 24 hForecasted winds: 24 h

Windspeedscale

Controlling layer where upslope flow is calculated

Forecastedmelting level

Observed bright-band snow level (White et al. 2002)

Model: Advanced Research WRF (ARW), 48-h durationGrid configuration: 3 km horizontal, 30 vertical levels

The middle panel displays theupslope component of the flow and the IWV

Observed IWVForecasted IWV

Forecasted upslope flowObserved upslope

flow

Upslopescale

Upslope direction defined

IWVscale

The thin horizontal lines define thresholds for IWV and upslope flow (2 cm and 12.5 m s-1; respectively) that were shown to

produce heavy rain (Neiman et al. 2008)

The IWV and upslope flow from the middle panel are combined to produce a bulk IWV flux, which is displayed in the bottom panel along with the

coastal and mountain hourly rainfall

Forecasted IWV flux Observed IWV flux

Observed rainfall (bars):Red = coastal siteGreen = mountain site

The thin blue horizontal line gives the IWV flux threshold (25 cm x m s-1) determined by multiplying the IWV and upslope flow thresholds defined in the middle panel

Forecasted rainfall (T posts):Red = coastal siteGreen = mountain site

Northern couplet: BBY & CZD

Orogr. forcingpredicted wellin this portionof the AR...

...but not theQPF, esp. inAR conditions.

next slide focuseson bottom panel

Time of max. IWV flux at BBY: 1500 UTC 4-Jan-084 Jan 2008, 1500 UTC

Time (UTC)

CZD rain: 264mmBBY rain: 36mm

4 Jan 2008, 2100 UTC Time of max. IWV flux at PPB: 2100 UTC 4-Jan-08

Time (UTC)

TPK rain: 320mmPPB rain: 75mm

5 Jan 2008, 0300 UTC Time of max. IWV flux at GLA: 0300 UTC 5-Jan-08

Time (UTC)

SMC rain: 230mmGLA rain: 51mm

AR Propagation: ~12 m s-1.½-day lead time for SoCal

Max. IWV flux in AR highly correlated withmax. mountain rainfall at each site

Summary – Part I• Ongoing research has led to the creation of a real-time vapor-flux tool to monitor

orographic rainfall forcing at multiple coastal sites.

• By combining observations and forecast model output, users can see how well a forecast model represents land-falling ARs and their resulting impacts on orographic rainfall enhancement.

• For the case shown, the WRF model reasonably captured parts of the orographic forcing. However, the coastal and mountain rains were predicted poorly (due to microphysics & terrain resolution?), and orographic forcing in the AR lasted longer in the model than observed (not shown).

• The three monitoring couplets deployed along the CA coast provided valuable lead time to forecasters for conditions leading to extreme rainfall.

• Given the absence of alternative monitoring capabilities for low-level water vapor flux at the coast, consideration is being given to the operational implementation of the above tool to fill this gap.

A Weather & Water Insurance Policy for California

Photo by Stephan Dietrich

Part IICA Department of Water Resources (DWR) Enhanced Flood Response

and Emergency Preparedness (EFREP) Program provides a legacy

for NOAA’s Hydrometeorological Testbed (HMT) Program

21st Century Observations Requirements/Drivers

• Flood Risks– Major basin hydrographs are more variable over last ~50 years

• Five highest flows on American River occurred since Folsom dam was built

• Similar results on Feather and San Joaquin Rivers– Earlier snowmelt combined with heavy spring storms raises flood risk

• Need to redefine probable maximum precipitation and include the impacts of rain on snow

• Water Resources– Uncertainty in storm intensity and annual rainfall will require adaptable

water management strategies– Should CA invest in more storage capacity or reoperate current

reservoirs using improved weather forecast information? (Forecast-Based Operations)

• Climate Change– 25% reduction in snow pack by 2050– Earlier snowmelt pushes peak runoff into winter storm period and

stresses water supply during dry season

Lester Snow, CA-DWR

--> Storage & transferability of water supplies will thus be at a premium.

Climate change may put some water managers in a real bind!

Next Generation Observations

Four primary “Tiers” envisioned for next generation observations based on concept and technology maturity and feasibility:

• Tier-I: Well-defined needs, proven technology, low cost• Tier-II: Well-defined needs, proven technology, moderate cost• Tier-III: Needs assessment and technology prototype tests in HMT-

West, high cost• Tier-IV: Offshore aircraft reconnaissance, potentially very high

cost/very high benefit

IV: Off-

shorerecon.

Tier III:Newer technology

Ex: Gap-filling radars,Buoy-mounted WPs

Tier I: Address well-defined needs with proven technology

Ex: Soil moisture sensors at CIMIS sites, GPS receivers of opportunity, snow-level radars

Tier II: Expand on well-defined needs with proven technology

Ex: Wind profilers, Coastal Atmospheric river observatory

A tiered approach for nex gen obs to help address CA’s water resource issues

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Soil moisture

Streamflow Cum. rainfall

Russian River at Healdsburg

Tier 1: Soil moisture monitoring at CIMIS sites

Date

• Adding soil moisture to select California Irrigation Management Information System (CIMIS) and other mountain rain gauge sites will improve stream flow prediction and monitoring

• Using existing infrastructure provided by CIMIS network greatly reduces costs associated with installation

• SIO (Scripps) proposed network of GPS receivers for geospatial applications (high resolution position mapping)

• Installing surface temperature and pressure sensors near these receiver sites will allow the network to map out the distribution of vertically integrated precipitable water vapor (IPW)

• Energy industry (electricity distribution) benefits because GPS receivers are used by Space Weather Center to monitor geomagnetic storms

Tier 1: GPS receivers of opportunity

Snow level

Tier 1: Snow level radars

• Provides precise snow-level height during precipitation events

• Utilizes proven FMCW technology to lower cost.

• Uses the patented ESRL automated snow-level detection algorithm (White et al. 2002) proven in CA field trials

• Less than 8’ diameter footprint• Low-power requiring minimal

infrastructure

Tier 1: Builds on existing networks and adds proven, low cost technologies:

• GPS-met • Soil moisture• Snow-level radars

Receivers already exist

Use existing CIMIS sites

At major reservoirs

Map of Tier I

CA GDP = $1.62 T$45k per capita

National Profiler Network of Japan Tier 2: Proposed Profiler Network

for CA

Sea of Japan

Pacific Ocean

Japan =374,744sq mi

CA =155,959sq mi

2005 data, sources:Wikipedia and U.S. Bureauof Economic Analysis

GNP = $4.66 Trillion, $38k per capita

California faces some of the same risks from winter storms that Japan faces with typhoons

Atmospheric River (AR) Observatory: Russian River PrototypeObjectives: Monitor key AR and precipitation characteristics.

Observing systems:1. Wind profiler/RASS2. S-band radar3. Disdrometer4. Surface met5. GPS-IWV6. Rain gauges

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W ind profiler/RASSS-band precip profilerGPS IW VSfc. met. + rain gaugeRaindrop disdrometer

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Tier 2: Atmospheric River Observatory

Tier 1: Builds on existing networks and adds proven inexpensive technologies:

• GPS-met • Soil moisture• Snow-level radars

Tier 2: Adds networks of proven, moderately expensive technologies:

• Wind profilers • Atmos. River Observatories• Providing more info aloft

Map of Tier I-II

Summary – Part II• A five-year Memorandum of Agreement has been signed by CA DWR

and NOAA to bring 21st century observation and modeling (not shown) capabilities to bear on the state’s flood protection and water resource management issues.

• The program will take advantage of existing state infrastructure to provide statewide networks of soil moisture and GPS integrated water vapor sensors.

• A new FM-CW S-band radar will provide critical measurements of the snow level during precipitation events to benefit a variety of end users.

• A west coast winter storms reconnaissance program is sorely missing. The NOAA Unmanned Aerial System (UAS) program may provide a viable platform for these missions.

ALTAIR at Channel Islands National Marine Sanctuary

Part IIIUnmanned Aerial Systems and the Pacific Testbed

Background

In 2005 NOAA formed an internal Unmanned Aerial Systems (UAS) Steering Committee and Working Group, which has subsequently identified a range of potential NOAA uses for UAS, including monitoring at-sea activities for fisheries and marine sanctuary enforcement purposes. Shown here are proposals for the possible future application of UAS technology in the accomplishment of NOAA’s missions in the Pacific.

Silver Fox in background on launcher and Manta in foreground

Humpback photographed from Silver Fox

Definition of UAS

UAS = Unmanned Aerial System

System is comprised of Subsystems:–Airframe (Platform)–Avionics and Communication:–Ground Control:–Launch and recovery–Payload:

•Sensors:–Scientific–Operational

Sensors (Operational)

• Optical• Infrared• Radar• Hyperspectral• AIS (Automatic Identification System)• Etc…

Sensors (Scientific)

• Dropsondes (for atmospheric temperature and moisture profiles)

• Cloud radar (a UAS version is under development)

• Microwave radiometer (for atmospheric moisture; one flown on Altair)

• Atmospheric composition/atmospheric chemistry (eg. ozone) sensors

Why and where would we use UAS in NOAA?

Missions that are:• Dirty (e.g., flying over forest fires)• Dull (e.g., searching for ocean debris)• Dangerous (e.g., flying over the Arctic)• Remote (e.g., long-endurance flights)• Unique mission requirements:

o Smaller and quieter UAS don’t disturb animals as much as a manned aircraft would

o Stealth provides advantages for surveillance and enforcement

o Persistenceo Better data resolution o Can be quickly deployed and positioned

Unmanned Aircraft Systems have great potential to fill this void and take observations to complement our existing platforms

Void between satellites and surface-based sensors

NOAA UAS Testbeds

NOAA UAS Testbeds

• Three testbeds are envisioned to be developed to support NOAA UAS experiments. They are nominally located in the Southeast, Alaska and the Pacific.

• The Southeast Testbed will be principally designed to support hurricane research and to support advanced severe weather prediction.

• The Alaska Testbed will aid in the study of the Arctic environment and global change research.

Pacific UAS Testbed• Mission objectives encompassing weather, air quality

monitoring, marine debris, marine mammal surveys, and fisheries enforcement

• Operations planned from NASA Dryden Flight Research Center and Barking Sands Pacific Missile Range Facility

• Targeting both low and high altitude demonstrations in 2009

• Initial focus to be on winter storms and atmospheric rivers

La Conchita Debris Flow Humpback whale photo from Silver Fox UASPotential operating locations

Low Altitude Atmospheric Rivers Mission

• Characterize the moisture flux from the ocean surface underneath an atmospheric river

• Partnering with Scripps Institute of Oceanography• Will utilize the Manta UAS• Instrumentation to include motion sensor and flux package• Test flights from Vandenberg AFB in October 2008 with scientific

mission in March 2009

5 Dec 07

Global Hawk Pacific Storms Mission

• Enhanced atmospheric profile observations to improve winter storm forecasts on the west coast

• Potential to combine observations for California water resources and atmospheric river studies

• Testing targeted for Summer 2009, mission goal of Winter 09-10• Measurements from dropsondes and, if available, a wind profiling lidar

Summary – Part III

• UAS have been used successfully in many military applications, but they are just starting to be used by civilian agencies, including NOAA.

• NOAA’s UAS program (http://uas.noaa.gov/) will establish three testbeds: Alaska focusing on global change issues, Southeastern U.S. focusing on Atlantic hurricanes, and Pacific focusing on weather, air quality, marine debris, marine mammal surveys, and fisheries enforcement.

• NOAA’s Pacific UAS Testbed will test and evaluate Global Hawk and Manta UAS platforms to monitor air-sea interaction and water vapor transport in atmospheric rivers imbedded in Pacific storms.

• Robbie Hood will become the new UAS project manager for NOAA in a couple of weeks. She will take over for Mart Ralph, who has served extremely well in this capacity for the past few years. Robbie will report directly to Sandy MacDonald, the director of ESRL and the Deputy Assistant Administrator for NOAA Research Laboratories and Cooperative Institutes and co-chair of the NOAA UAS Steering Committee.

Thank you!