Heat and Health: Methodological Considerations for Warning System

Development

Public Weather Program Leader’s MeetingMinneapolis, MN - June 24, 2003

Dr. Laurence S. KalksteinCenter for Climatic Research

University of Delaware

How Are These Systems Unique?

A custom-made system is developed for each urban area, based on specific meteorology for each locale, as well as urban structure and demographics

These systems are based on actual weather-health relationships, as determined by daily variations in human mortality

These systems are based on much more than just temperature and humidity

World Meteorological OrganizationShowcase Projects

Center for Climatic Research, University of Delaware

Participating Cities: - Dayton/Cincinnati, USA- New Orleans, USA- Philadelphia, USA- Phoenix, USA- Rome, Italy- Shanghai, China- Toronto, Canada- Washington, USA- Five additional cities, Southern USA- Chicago/St. Louis, New for 2003

Maximum Temperature vs. Daily Mortality: New York and Jacksonville, Florida

New York Jacksonville

Maximum Temperature Health Thresholds

Boston 30ºC

Atlanta 32ºC

Dallas 40ºC

Denver 34ºC

Phoenix 44ºC

Cook County, Illinois: July ‘95

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Steps in System Development

Step 1: Determine air masses daily over a city using newly-developed Spatial Synoptic Classification (SSC)

Step 2: Are any of these air masses ‘offensive’?

Step 3: What aspects of the offensive air mass make it most detrimental to human health?

SSC Air Mass Types• DP Dry Polar (cP)• DM Dry Moderate (Pacific)• DT Dry Tropical (cT)• MP Moist Polar (mP)• MM Moist Moderate (Overrunning)• MT Moist Tropical (mT)• MT+ Moist Tropical Plus• TR Transition between air masses----------------Sheridan, S.C., 2002: The redevelopment of a weather-type classification scheme for North America.

Int’. J. Climatology.Kalkstein et al., 1996, A New Spatial Synoptic Classification: Application to Air Mass Analysis. Int.

J. Climatology.

Characteristics of PittsburghAir Mass Types

Frequency (%) 33.7 12.6 3.5 16.8 4.4 20.6 8.45 pm 5 pm 5 am Cover Direction Freq.DP 74 49 54 4 NW 11%DM 83 56 61 4 W 29%DT 95 58 69 4 W 2%MP 67 60 60 8 NE 5%MM 76 65 64 7 SW 22%MT 84 66 68 6 SW 18%MT+ 90 71 73 5 SW 5%TR 77 57 64 7 Var 7%

Removing Non-Climatological Noise from the Mortality Data

Phoenix’s Rising Mortality

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Mean Deaths in Rome by Daystandardization is important

Results: Offensive Air Mass Types

• Moist Tropical Plus (MT+):– Very warm, humid– High overnight temperatures

• Dry Tropical (DT):– Hot, dry– High solar load

• Dry Tropical Plus (DT+; Phoenix only):– Extremely hot, dry– High solar load

Mean Mortality Increases

Location (Freq) DT (DT+) MT+

Cincinnati (8%) +4.4 (15%) +1.8 (6%)

New Orleans (2%) None +3.7 (9%)

Phoenix (1%) +2.7 (7%) None

Rome (11%) +6.2 (14%) +5.0 (12%)

Shanghai (12%) None +42.4 (16%)

Toronto (7%) +4.2 (11%) +4.0 (10%)

Mean Anomalous Mortality by Weather Type, Rome

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(7.0%) (4.3%)

Mean Anomalous Mortality by Weather Type, Shanghai

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Likelihood of Excess MortalityToronto

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Development of Forecast Algorithms: Within-Air Mass Category

Mortality Variations

ROME

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ROME

DT mortality vs. morning temperature

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Impact of Consecutive Days of Offensive Air Masses

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In Toronto, When a DT or MT+ Air Mass is Forecast, Three Levels of

Advisory are Possible:

Year-to-Year Variability: Toronto

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Emergency

Advisory and Emergency Frequencies: Phoenix, AZ

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ADVISORY D1/D2 EMERGENCY

Summary of Watches/Warnings Under NWS System andAir Mass System, Summer 2001

New Orleans, Louisiana

Toronto: 2001 Results

Alerts• June 29th (DT 71%)• July 23rd (MT+ 88%)• July 24th (MT+ 84%)• Aug 5th (DT 65%)

Emergencies• June 15th (MT+ 96%)• Aug 6th (DT 91%)• Aug 7th (DT 93%)• Aug 8th (DT 97%)• Aug 9th (DT 99%)

Four day run of heat emergencies Aug 6-9 would have only occurred two other times in the 46 years for which data was provided.

Steps That can be Taken When Alerts or Emergencies are Called

1. NWS alerts appropriate city agency (e.g., Department of Health, Office of Aging, etc.)

2. City develops (or already has in place) intervention plans

3. Effectiveness of system can be monitored in three manners,and improvements are implemented if there are shortcomings:--forecasting effectiveness (false positives or negatives)--accuracy in estimating health impacts of offensive weather --noting if we are saving lives.