1. The influence of air mass circulation patterns on the urban heat island intensity and fire risk weather in Helsinki Testbed
Andrea Vajda, Achim Drebs
Finnish Meteorological Institute

2. Motivation of the study
The availability of the high resolution ground and low atmosphere observation allows the detailed analyses of the urban heat island, soil moisture and fire risk.
Objectives
To evaluate the behavior of urban boundary layer in two circulation patterns
To estimate the urban heat island intensity in HTB under the given circulation patterns
To evaluate the spatial and temporal variation of soil moisture and its determining variables in HTB under the given circulation patterns

3. South-western circulation
Air mass circulation patterns used in this study
South-western circulation
Northern circulation
Ilmatieteen laitos / PowerPoint ohjeistus
11/27/2018

4. Location of ceilometers
Data used in the project
ceilometers: HTB (6 ?)
air temperature (2 m): HTB, FMI, MCN
precipitation – gauges: HTB, FMI
– radar observation
soil moisture data: FMI (10*10 km2)
forest fire index: FMI (10*10 km2)
Location of ceilometers
and studied area

5. Working process and outputs
Data collection
Urban heat island
Soil moisture and forest fire risk
Spatial distribution of heat island during the two types of circulation
Spatial variation of temperature (1*1 km2)
Spatial variation of precipitation (1*1 km2)
Soil moisture maps (10*10 km2)
Fire index maps (10*10 km2)
How the studied air mass circulation types influens the development
of urban heat island and forest fire variation?