Colorado Basin River Forecast Center and Drought Related Forecasts Kevin Werner.
Monitoring Drought: Current Products and Technologies Mark Svoboda National Drought Mitigation...
-
Upload
angelica-gilbert -
Category
Documents
-
view
216 -
download
0
Transcript of Monitoring Drought: Current Products and Technologies Mark Svoboda National Drought Mitigation...
Monitoring Drought:Current Products and
Technologies
Mark SvobodaNational Drought Mitigation Center
International Drought Information CenterUniversity of Nebraska-Lincoln
Components of a Drought Plan
monitoring, early warning and prediction
risk and impact assessment
mitigation and response
Spatial Extent
Drought Monitoring Questions
Where are we now?
How did we get here?
What is the historical perspective for the current situation?
What are the most likely outcomes from the current situation?
The Importance of a Drought Monitoring System
allows for early drought detection
improves response (proactive)
“triggers” actions within a drought plan
a critical mitigation action
Components of a Drought Monitoring System
timely data and timely acquisition
synthesis/analysis of data used to “trigger” set actions within a plan
efficient dissemination network (WWW, media, extension, etc.)
An integrated climate monitoring system needs to:
be comprehensive in scope (coupling climate, soil and water data)
incorporate local and regional scale data
utilize improved indices and triggering tools (latest technology)
improve impact estimation
be flexible to various user’s needs
Potential Monitoring System Products and Reports
Historical analysis (climatology, impacts, magnitude, frequency)Operational assessment (cooperative data, SPI and other indices, automated networks, satellite and soil moisture data)Predictions/Projections (SPI and other indices, soil moisture, streamflow, seasonal forecasts, SST’s)
Key Variables For Monitoring Drought
climate datasoil moisturestream flowground waterreservoir and lake levelssnow packshort, medium, and long range forecastsvegetation health/stress and fire danger
Importance of Drought Indices
Simplify complex relationships and provide a good communication tool for diverse audiences
Quantitative assessment of anomalous climatic conditions
Intensity
Duration
Spatial extent
Historical reference (probability of recurrence)
Planning and design applications
Triggers: thresholds determining specific, timely actions by decision makers
• appropriate• consistent with impacts• adaptable
Triggers need to be:
Indicators & Triggers Definitions
Indicators: Variables to describe drought conditions.
Examples: precipitation, streamflows, groundwater, reservoir levels, soil moisture, Palmer indices, …
Triggers: Specific values of the indicator that initiate and terminate each level of a drought plan, and associated management responses.
Example: precipitation below the 5th percentile for two consecutive months Level 4 Drought.
(From GA State Plan)
Considerations in Choosing Indicators / Triggers
Proper and Timely Detection of Drought Spatial and Temporal SensitivitySupplies and DemandsDrought In / Drought OutComposite and Multiple IndicatorsData Availability, Validity, and ClarityEase of Implementation
(From GA State Plan)
Problems with Typical Indicators Scales
Drought categories not comparable among indicators
(SPI “extreme” is different than PDSI/PHDI “extreme”)
Varying probability differentials for equal index differentials
(SPI –2 to –1 is 13.6%; SPI –1 to 0 is 34.1%)
Lack of temporal and spatial consistency
PDSI, extreme drought: < 1% , Jan., Northwest; > 10%, July, Midwest
SPI Drought Category Cumulative Frequency
0.00 to – 0.99 Mild 16%-50%
–1.00 to –1.49 Moderate 6.8%-15.9%
–1.50 to –1.99 Severe 2.3%-6.7%
–2.00 or less Extreme < 2.3%
PDSI/PHDI Drought Category Cumulative Frequency
0.00 to –1.49 Mild 28%-50%
–1.50 to –2.99 Moderate 11%-27%
–3.00 to –3.99 Severe 5%-10%
–4.00 or less Extreme < 5%
(From GA State Plan)
Problems with Typical Indicators Scales
Difficulty using multiple indicators
(Indicators units not validly combined; Triggers not statistically comparable)
DroughtCategory SPI Streamflow
(cfs)Groundwater
(ft)Reservoir Level
(ft)
Mild (1) 0.00 to – 0.99 > 1000 < 45 > 1065
Moderate (2) –1.00 to –1.49 700 - 1000 45 - 50 1055 - 1065
Severe (3) –1.50 to –1.99 400 - 700 50 - 55 1050 - 1055
Extreme (4) –2.00 or less < 400 > 55 < 1050
(From GA State Plan)
A Solution: Indicators Based on Percentiles
Raw indicator data converted to percentiles (cumulative frequency)
Triggers based on percentile thresholds for each Drought Category (level)
Triggers for each indicator correspond to those percentiles
(e.g., groundwater level of 51.1 ft. is the 35th percentile; 54.0 ft.is the 20th percentile)
DroughtCategory
Percentile SPI Streamflow(cfs)
Groundwater(ft)
ReservoirLevel (ft)
Mild (1) 0.20 – 0.35 - 0.39 1346 51.1 1062.6
Moderate (2) 0.10 – 0.20 - 0.84 518 54.0 1061.1
Severe (3) 0.05 – 0.10 - 1.28 267 56.3 1058.4
Extreme (4) 0.00 – 0.05 - 1.64 160 57.7 1056.5
(From GA State Plan)
Drought Levels(based on percentiles)
Percentile0.50-1.00
0 0.35-0.501 0.20-0.352 0.10-0.203 0.05-0.104 0.00-0.05
Level 2 Level 3 Level 4
Category Normal/Wet
Near-normal/dryLevel 1
(From GA State Plan)
Triggering GoalsAdvance warning going in (while avoiding false alarms)
Conservative going out (while avoiding unnecessary restrictions)
Smooth transition going in and going out
Ease of understanding and implementation
Trigger in: from less severe to more severe drought level
Trigger out: from more severe to less severe drought level
Consistent with historic conditions
Which triggers would have performed “best”?
(From GA State Plan)
Triggering Sequence Methodology
Drought “in’ and “out” triggers:
• For going into a drought ("in" triggers): When any one of the triggers is at a certain (or more severe) level for at least two consecutive months, then that level is invoked. The primary "in" trigger is the SPI-6, unless another trigger invokes Level 1 first. In that case, the other trigger becomes the primary trigger until the SPI-6 catches up (to an equal or more severe level), and then takes over.
• For getting out of a drought ("out" triggers): When all of the triggers are at a certain (or less severe) level for at least four consecutive months, then that level is invoked. The first "out" trigger should be the first "in" trigger. Then additional "out" triggers need to be met before moving to a less severe level of drought.
(From GA State Plan)
Future Needs and Recommendations
Real-time testing of triggersFeedback from stakeholdersCoordination at different scalesData collection and analysesSupplement to human expertise
(From GA State Plan)
Triggers: State of South CarolinaIncipient Drought Alert Phase:PDI -.50 to -1.49CMI 0.00 to –1.49SPI -1.0 to –1.49KBDI 300 to 399Drought Monitor D0ADS is 111-120% of the minimum flow for 2 consecutive weeksSWL in aquifer is between 11 to 20 ft. above trigger level for 2consecutive months
Moderate Drought Alert Phase:PDI -1.50 to –2.99CMI -1.50 to –2.99SPI -1.50 to –2.00KBDI 400 to 499Drought Monitor D1ADS 101-110%/SWL 1-10 ft above trigger level
Triggers: State of South CarolinaSevere Drought Alert Phase:PDI -3.00 to –3.99CMI -3.00 to –3.99SPI -2.01 to –2.99KBDI 500 to 699Drought Monitor D2ADS between min flow and 90% of the min flow for 2 consecutive weeksSWL between trigger level and 10 ft. below trigger levelfor 2 consecutive monthsExtreme Drought Alert Phase:PDI -4.00 and belowCMI -4.00 and belowSPI -3.00 and belowKBDI 700 and aboveDrought Monitor D3/D4ADS < 90% of min flow/SWL > 10 ft. below trigger level
Triggers: Denver Water
80 percent full Mild drought
60 percent full Moderate drought
40 percent full Severe drought
If predicted or actual July 1 storage is below…
Declaration would be...
Considerations for Selecting a Specific Trigger or Index:
Is the information readily available?Can an index/trigger be calculated in a timely manner? Is the information likely to remain available over time?Is the information likely to remain available over time? Can the index/trigger be meaningfully correlated to actual conditions?
1) No single parameter is used solely in determining appropriate actions
2) Instead, different thresholds from different combinations of inputs is the best way to approach monitoring and triggers
3) Decision making (or “triggerstriggers”) based on quantitative values are supported favorably and are better understood
Critical Observations:
Approaches to Drought Assessment
Single index or parameter
Multiple indices or parameters
Composite index
Mark Svoboda National Drought Mitigation Center
Making the Drought Monitor:Putting the Pieces Together
With ContributionsFrom:
Richard Heim,NCDC
David Miskus,CPC-JAWF
Brad Rippey,USDA-JAWFMike Hayes,
NDMCDoug LeComte,
CPCRich Tinker,
CPC
The Drought Monitor Overview
History – Background - Objectives
Participants
Procedure
Input Indicators
User Feedback
Challenges
The U.S. Drought MonitorSince 1999, NOAA (CPC and NCDC), USDA, and the
NDMC have produced a composite drought map -- the U.S. Drought Monitor -- each week with input from
numerous federal and non-federal agencies
Why the Recent Interest in Drought in the U.S.?
Single and multi-year severe droughtsintensity and duration
western and eastern U.S.
Spatial extent—40 to 50% of U.S. in 2002
Complexity of impacts VulnerabilityAgriculture, energy, transportation, urban water supply, recreation/tourism, fires, environmental, social
Conflicts between water users
Water restrictions (agricultural and urban)
Trend toward drought mitigation planning
Media coverage
Why Monitor Drought?
Drought is a Normal Part of the Climatic CycleDrought Impacts are Significant & WidespreadMany Economic Sectors AffectedDrought is Expensive
Since 1980, major droughts and heat waves within the U.S. alone have resulted in costs exceeding 100 billion dollars
Recent Drought Lossesin the U.S.
1988: $39.2 billion nationwide
1993: $1 billion across the Southeast
1996: $10 billion across the Southwest
1998: $6-8 billion across the South
1999: $1 billion along the East Coast
2000: $1 billion each in Nebraska, Oklahoma, Texas, and Georgia
2002: >$20 billion nationwide??
2003: $$ billion ????Average annual losses: $6-8 billion (FEMA)
Original Objectives
“Fujita-like” scale
U.S. Drought Monitor Map
Drought Intensity Categories
D0 Abnormally Dry
D1 Drought – Moderate
D2 Drought – Severe
D3 Drought – Extreme
D4 Drought – Exceptional
Original Objectives
“Fujita-like” scale
NOT a forecast!
Identify impacts (A, H)
Assessment of current conditions
Incorporate local expert input
Be as objective as possible
Drought Severity Classifications
**Indices used primarily during the snow season and in the West include the River Basin Snow Water Content, River Basin Average Precipitation and SWSI
U.S. Drought Monitor Several key and ancillary indicators Attempts to capture conditions across wide
spectrum of drought conditions
Must Address: No single definition
of drought Integrates many
indicators Now creating in
ARC GIS
Indices for“The West”
Other Drought Indicators (Used with Caution):
Reservoir levelsGround Water levelsStreamflow levelsSatellite SSMI Wetness
Objective BlendsOperationally integrate multiple indicators in
a weekly update using a percentile ranking method
Produced weekly using CPC’s real-time daily and weekly climate division data and NCDC’s monthly archive of indices for 1932-2000
All parameters are first rendered as percentiles with respect to 1932-2000 data using a percent rank method
Short- and Long-Term Blends produced
Objective Blends
Short-Term Blend
35% Palmer Z Index25% 3-Month Precip.20% 1-Month Precip.13% CPC Soil Model7% Palmer Drought Index
Objective Blends
Long-Term Blend
25% Palmer Hydrological Index20% 24-Month Precip.20% 12-Month Precip.15% 6-Month Precip.10% 60-Month Precip.10% CPC Soil Model
ObjectiveBlends
Useful for showing situations and areas having similar trends or opposite trends in moisture conditions
Monitor Development Development (Period starts 12Z last Tuesday)(Period starts 12Z last Tuesday)
Monday (5 Days available)
Draft map sent to local experts
ThursdayFinal map & text released on NDMC Website
Tuesday (6 Days available)
Local expert feedbackDraft map sent to local expertsDraft text sent to local experts
Wednesday (7 Days available; ending 12Z yesterday)
Local expert feedback Draft map(s) sent to local experts Draft text(s) sent to local experts (Outlook) Final map and text sent to secured ftp server
The Importance of Local Expert Input
The National Centers can produce a variety of input indicator products(e.g., CPC station dot map)These give us “The Big Picture”
The Importance of Local Expert Input
The U.S. Drought Monitor Team Relies on Field Observation Feedback from the Local Experts for Impacts Information & “Ground Truth”
Listserver (140-150 Participants: 2/3 Federal, 1/3 State/Univ.)
Local NWS & USDA/NRCS Offices
State Climate Offices
State Drought Task Forces
Regional ClimateCenters
Midwest Regional Climate Center
The Importance of Local Expert Input
High PlainsRegional
Climate Center
The Importance of Local Expert Input
Western Regional Climate Center Colorado Climate Center
The Importance of Local Expert Input
Montana StateDrought Advisory Committee
Oregon State Climatologist Office
Observed real-time data are essential:for timely drought assessments (real-time and historical)for increased spatial and temporal resolutionas input for generating many climate products/forecasts “ground truthing” of soil moisture (and other) models“ground truthing” of radar precipitation estimatesgetting information to decision makers when they need it…….i.e. yesterday!filling in data sparse areas
Real-Time NWS Cooperative Real-Time NWS Cooperative Observer NetworkObserver Network
www.coop.nws.noaa.gov
Automated Weather Networks
Automated Weather Networks
Mesonet Sites Approx. 1,000 in the U.S.
http://drought.unl.edu/dm
Future Challenges
Incorporate groundwater, streamflow, reservoirs, AHPS data as more real-time
data become available
Develop a sister hydro DM equivalent: The Water Resources Monitor??
Support and utilize the development of a western SWSI tool (BWI—Basin Water Index)
Incorporate USDA soil moisture (i.e. SCAN) and/or Mesonet soils data
Next Steps
North American DM is currently being produced “experimentally”
Taking the DM into a new spatial realm?
Robust IMS/GIS query/analysis potential
ACIS---Applied Climatological Information System. Effort taking daily climate data from NOAA’s COOP network, SCAN, SNOTEL, along with state and regional Mesonet data
Incorporate new tools: ACIS, remote sensing, NADSS, soil moisture sensors, etc.
National Drought Mitigation Centerhttp://drought.unl.edu/dm
http://drought.unl.edu