Monitoring Drought: Current Products and Technologies Mark Svoboda National Drought Mitigation Center International Drought Information Center University 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 data soil moisture stream flow ground water reservoir and lake levels snow pack short, medium, and long range forecasts vegetation 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tool for diverse audiences Quantitative assessment of anomalous climatic conditions Intensity Duration Spatial extent Historical reference (probability of recurrence) Planning and design applications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 Sensitivity Supplies and Demands Drought In / Drought Out Composite and Multiple Indicators Data Availability, Validity, and Clarity Ease 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: 10%, July, Midwest (From GA State Plan)

Problems with Typical Indicators Scales Difficulty using multiple indicators (Indicators units not validly combined; Triggers not statistically comparable) (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) (From GA State Plan)

Drought Levels (based on percentiles) (From GA State Plan)

Triggering Goals Advance 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 triggers Feedback from stakeholders Coordination at different scales Data collection and analyses Supplement to human expertise (From GA State Plan)

Triggers: State of South Carolina Incipient Drought Alert Phase: PDI -.50 to CMI 0.00 to –1.49 SPI-1.0 to –1.49 KBDI300 to 399 Drought MonitorD0 ADS is % of the minimum flow for 2 consecutive weeks SWL in aquifer is between 11 to 20 ft. above trigger level for 2 consecutive months Moderate Drought Alert Phase: PDI-1.50 to –2.99 CMI-1.50 to –2.99 SPI-1.50 to –2.00 KBDI400 to 499 Drought MonitorD1 ADS %/SWL 1-10 ft above trigger level

Triggers: State of South Carolina Severe Drought Alert Phase : PDI-3.00 to –3.99 CMI-3.00 to –3.99 SPI-2.01 to –2.99 KBDI500 to 699 Drought MonitorD2 ADS between min flow and 90% of the min flow for 2 consecutive weeks SWL between trigger level and 10 ft. below trigger level for 2 consecutive months Extreme Drought Alert Phase: PDI-4.00 and below CMI-4.00 and below SPI-3.00 and below KBDI700 and above Drought MonitorD3/D4 ADS 10 ft. below trigger level

Triggers: Denver Water 80 percent fullMild drought 60 percent fullModerate drought 40 percent fullSevere 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 triggers 3) Decision making (or “triggers”) 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 Contributions From: Richard Heim, NCDC David Miskus, CPC-JAWF Brad Rippey, USDA-JAWF Mike Hayes, NDMC Doug LeComte, CPC Rich Tinker, CPC

The Drought Monitor Overview History – Background - Objectives Participants Procedure Input Indicators User Feedback Challenges

The U.S. Drought Monitor Since 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 droughts intensity and duration western and eastern U.S. Spatial extent—40 to 50% of U.S. in 2002 Complexity of impacts  Vulnerability Agriculture, 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 Cycle Drought Impacts are Significant & Widespread Many Economic Sectors Affected Drought is Expensive Since 1980, major droughts and heat waves within the U.S. alone have resulted in costs exceeding 100 billion dollars

Recent Drought Losses in 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 levels Ground Water levels Streamflow levels Satellite SSMI Wetness

Objective Blends Operationally 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 All parameters are first rendered as percentiles with respect to data using a percent rank method Short- and Long-Term Blends produced

Objective Blends  Short-Term Blend 35% Palmer Z Index 25% 3-Month Precip. 20% 1-Month Precip. 13% CPC Soil Model 7% Palmer Drought Index

Objective Blends  Long-Term Blend 25% Palmer Hydrological Index 20% 24-Month Precip. 20% 12-Month Precip. 15% 6-Month Precip. 10% 60-Month Precip. 10% CPC Soil Model

Objective Blends Useful for showing situations and areas having similar trends or opposite trends in moisture conditions

Development (Period starts 12Z last Tuesday) Monitor Development (Period starts 12Z last Tuesday) Monday (5 Days available) Draft map sent to local experts Thursday Final map & text released on NDMC Website Tuesday (6 Days available) Local expert feedback Draft map sent to local experts Draft 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 ( Participants: 2/3 Federal, 1/3 State/Univ.) Local NWS & USDA/NRCS Offices State Climate Offices State Drought Task Forces Regional Climate Centers Midwest Regional Climate Center

The Importance of Local Expert Input High Plains Regional Climate Center

The Importance of Local Expert Input Western Regional Climate Center Colorado Climate Center

The Importance of Local Expert Input Montana State Drought 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 resolution as input for generating many climate products/forecasts “ground truthing” of soil moisture (and other) models “ground truthing” of radar precipitation estimates getting information to decision makers when they need it…….i.e. yesterday! filling in data sparse areas

Real-Time NWS Cooperative Observer Network

Automated Weather Networks

Mesonet Sites Approx. 1,000 in the U.S.

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.

Drought Impacts Impacts are increasing in complexity and magnitude—a sign of increasing vulnerability No systematic national assessment FEMA estimates annual drought losses at $6-8 billion (1995) 1988 drought costs and losses estimated at $39 billion (>$15 billion in crop losses) 2002 drought losses estimated at >$20 billion (conservative estimate)

Drought Impacts in the US September 9 - October 6, 2000

Western Drought Coordination Council Local Drought Response Information Preparedness and Mitigation Working Group March 1999 Principal Author: Tom Phillips, U.S. Bureau of Reclamation