gerd.jendritzky@meteo.uni-freiburg.de

The Thermal Environment of the Human Being

- A subjective retrospection on methodologies -

Gerd Jendritzky1 and George Havenith2

1Meteorological Institute, University of Freiburg, Germany2Environmental Ergonomics Research Centre, Loughborough University, U.K.

g.havenith@lboro.ac.uk

Overview

• Applications (selected examples)• Basics in heat exchange• Simple Climate Indices• Heat Balance Models• The Future: Incorporating the Human• Provocative remarks

Why?

• Assessment of the thermal environment:

Key issue in human biometeorology!

Applications

• Public weather service

• Public health system

• Precautionary planning

• Climate impact research

christina.koppe@dwd.de DWD 2004

Human Biometeorology

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

1

11.0

2.03

25.0

2.03

11.0

3.03

25.0

3.03

08.0

4.03

22.0

4.03

06.0

5.03

20.0

5.03

03.0

6.03

17.0

6.03

01.0

7.03

15.0

7.03

29.0

7.03

12.0

8.03

26.0

8.03

09.0

9.03

23.0

9.03

0

20

40

60

80

100

120

140

160

mo

rtal

ity

(%);

PT

(°C

)

hypothetical warning

PT (°C)

mortality (%)

Modelled Heat Load and Observed Mortality 2003, Baden-Württemberg

Heat related extra deaths in Europe, August 2003

UTC13:00

heat load

cold stress

slight

extreme

strong

moderate

slight

comfortable

moderate

strong

extreme

• 7000• 2045 • 1400

• 150

• 14805

• 4175• 4230

01915462810F(%) =

Paris (1991 - 1998)

Thermal stress category

43210-1-2-3

Mor

talit

y

150

140

130

120

110

10090

0 0 4 13 55 27 0 0F(%) =

London (1976 - 2000)

Thermal stress category

43210-1-2-3

Mor

talit

y (%

)

150

140

130

120

110

10090

021318333130F(%) =

Budapest (1972 - 2001)

Thermal stress category

43210-1-2-3M

orta

lity

(%)

150

140

130

120

110

10090

0 1 12 18 40 27 10F(%) =

SW Germany (1968 - 2003)

Thermal stress category

43210-1-2-3

Mor

talit

y (%

)

150

140

130

120

110

10090

0 2 17 28 48 500F(%) =

Lisbon (1981 - 1998)

Thermal stress category

43210-1-2-3

Mor

talit

y (%

)

400

350

300

250

200

150

10050

0 2 17 28 48 500F(%) =

Lisbon (1981 - 1998)

Thermal stress category

43210-1-2-3

Mor

talit

y (%

)

150

140

130

120

110

10090

Human Biometeorology

Mortalityby Thermal Stress

(Koppe, 2004)

gerd.jendritzky@meteo.uni-freiburg.de

hei

ght

U

width

26

30

34

38

42

Tair

wind

PT

°C

T surface

TMRT

30 32 34 °CTwall T

34 36 38°Cwall

PT

angelika.graetz@dwd.de

Berlin

frequency of heat load

Business Unit Human Biometeorology

The heat wave 2003 in Europe:A unique feature?

IPCC WGI, 2001:

“Higher maximum temperatures and more hot days over nearly all land areas are very likely”

5 10 15 20 25 30 35 40 45 50

Average summer Tmax [°C]

0

.02

.04

.06

.10

.08

Fre

qu

ency

1961-1990(obs)

1961-1990(mod) 2071-2100

2003

Beniston, 2004

Need to adapt

birger.tinz@dwd.dedata: Deutsches Klimarechenzentrum Hamburg; ECHAM4/T106

July Delta Perceived Temperature (K), (IS92a-CTL)

cold warm

Body Core Temperature

Heat Production

Heat Loss

Heat Balance

The human heat budget

M + W + Q* + QH + QL + QSW + QRe + S = 0

M Metabolic rate

W Mechanical power

Q* Radiation budget (Tmrt,v)

QH Turbulent flux of sensible heat (Ta,v)

QL Turbulent flux of latent heat (diffusion water vapour) (e,v)

QSW Turbulent flux of latent heat (sweat evaporation) (e,v)

QRe Respiratory heat flux (sensible and latent) (Ta,e)

S Storage

I Assessment Procedures

Simple (mostly two-parameter) thermal indices,„comfort indices“ (> 100 known)

Examples: Air temperature Ta Heat index (Ta, RH) Windchill Index (Ta, v) WBGT

Principle

Each value of an index must result in the same thermophysiologial effect,

regardless of the combinations the meteorological and other environmental input values.

No simple index is able to fulfill this requirement!

II Assessment Procedures

Weather classifications (holistic approach)(e.g. Kalkstein et al.)

• Successful in health studies• Successful in HHWSs

conduction

convection

respiration

Sweat evaporation

clothing

Direct radiation

Sun or other

radiation source

Reflectedradiation

Infra-redradiation

infra-redradiation

M

External work

Avenues of Heat Exchange

Havenith, 2003

Assessment ProceduresSimple index

Heat balance model

The Comfort Equation

Fanger, 1970

Problems

• Heat balance models assume “steady state” condition of the human body

• Models only consider two nodes (core and shell)

• Physiological response is simplified

Physiological reaction to body cooling

Havenith, 2005

Skin Temperature

Havenith/ Adidas, 2004

Future ExpansionSimple index

Heat balance model

HumanPhysiologymodel

Tcore

Tskin

Skin Blood Flow

Sweating

Shivering

Brain Controllers

Behaviour

SkinTemperature

Threshold

+ -

CoreTemperature

Threshold

+ -

Environment

HeatExchange

HeatExchange

Human Physiology ModelControl System

Havenith, 2001

Fiala et al., 2001

Future ExpansionSimple index

Heat balance model

HumanPhysiologymodel

European COST Action 730:Universal Thermal Climate Index (UTCI)

Action 730 on UTCI

Fiala et al. 2001

Final Provocative Remarks

• Temperature related mortality: People die from heat load!• Holistic approaches: For what when we basicly know the

physiological link!• Simple thermal indices:

- Former times: Lack of knowledge

- Later : No access to computer facilities

- Since years : Ignorance of physiological basics• Complete heat budget models state-of-the-art• Future: Human response related improved models UTCI

• Shouldn‘t scientific journals reject manuscripts not based on state-of-the-art?