Mesoscale Observing Network Course The Sea Breeze Project

Mesoscale Observing Network Course The Sea Breeze Project Reijo Hyvönen, FMI Christer Helenelund, Vaisala

Suggested project title Characteristics of sea breeze at the Finnish South Coast ©Vaisala | CH | December 2006 | Page 2

Introduction Purpose/goal • To clarify the sea breeze conditions on the Finnish South Coast using HTB data What is done/methodology • Pick suitable dates to study (May 6, May 10, July 6 and July 8, 2006) • Collect, summarize and analyze wind data from masts and wind profiler for these days for two cross sections along the coast • Draw conclusions from the data obtained ©Vaisala | CH | December 2006 | Page 3

Measurement campaigns of HTB phase 1 May 2005 testing August 2005 (no database, limited instrumentation) • convection, nowcasting by extrapolation • World Championships in Athletics November 2005 • snow/rain January-February 2006 • inversions May 2006 • sea breeze • fog August 2006 • convection ©Vaisala | CH | December 2006 | Page 4

Measurement lines ©Vaisala | CH | December 2006 | Page 5

Idealized sea breeze circulation ©Vaisala | CH | December 2006 | Page 6

Measurement station in conjunction with cellular base station Weather transmitter h = 40. . . 100 m Station specific URL address for Internet access Weather transmitter h=2 m ©Vaisala | CH | December 2006 | Page 7 Cell phone data transfer module and power supply

Malmi Wind Profiler (Vaisala LAP-3000) Photo from Malmi airport ©Vaisala | CH | December 2006 | Page 8

SYNOP 2006 -05 -06 ©Vaisala | CH | December 2006 | Page 9

Wind Profiler measurements 2006 -05 -06 ©Vaisala | CH | December 2006 | Page 10

Wind Profiler measurements 2006 -07 -28 ©Vaisala | CH | December 2006 | Page 11

Wind measurements 2006 -05 -06 03: 30 UTC ©Vaisala | CH | December 2006

Wind measurements 2006 -05 -06 11: 45 UTC ©Vaisala | CH | December 2006

Wind measurements 2006 -05 -06 18: 00 UTC ©Vaisala | CH | December 2006

Wind measurements 2006 -05 -06 20: 15 UTC ©Vaisala | CH | December 2006

Sea breeze front 2006 -07 -28 Reflections from insects & birds (swallows, swifts) ©Vaisala | CH | December 2006 | Page 16

Initial comments • Limited HTB data available -> Too small statistical basis for finding common patterns • Many days with unclear sea breeze effect • The general weather pattern (the geostrophic wind and scattered cloudiness) makes very often the sea breeze weaker or even or non-existent • The scattered archipelago makes the coast line diffuse and also the sea breeze unclear • The scattered topography impacts also the local wind (tunneling effect) • The albedo on the shore varies quite much along the coast • On top of all this, there is obviously the normal stochastical variation in the wind • Based on this it might be difficult to make any solid conclusions ©Vaisala | CH | December 2006 | Page 17