Portland, Oregon Climate

Blog #3

This blog will discuss the climate of Portland, Oregon, what meso-scale and micro-scale effects impact the weather station, the region's recent climate history, and where the area lies in the Koppen-Geiger classification system.  Meso-scale impacts come from the region's proximity to the Pacific Ocean, and its location on the western side of the North American Continent.  It is affected by multiple air masses, dominantly Maritime Tropical and Maritime Polar, and occasionally Continental Polar.  Winter months bring more precipitation from mid-latitude cyclones, while summer months are dryer from subtropical highs.  Micro-scale climate impacts come from the station's location near the Columbia River at the airport of the United States's 29th largest city.  This creates higher temperatures due to urban heat island effects from nearby industrial areas.  However, this is offset by the station's location in a valley near a flowing body of water which will lower temperatures immediately adjacent to the river.  

The following graphs show annual climate data in Portland Oregon.  

Years prior to 1941 report a weather station in downtown Portland, 1941 and later report the airport.

http://www.wrh.noaa.gov/pqr/pdxclimate/

http://www.wrh.noaa.gov/pqr/pdxclimate/

http://www.wrh.noaa.gov/pqr/pdxclimate/

These graphs reflect a general warming and drying trend over the past 140 years.  Both climate change and urban heat island effects could be the reasons for the difference.  Portland's population grew from 8,293 in 1870 to 583,776 in 2010, and accompanying industrialization occurred during this time.  This has the immediate effect of raising temperatures in urban areas.  Climate change will also affect regions with this climate by intensifying the dry summers, potentially decreasing available water supplies.

Koppen-Geiger Classification Map of North America

Portland is categorized as Csb on the Koppen-Gieger climate scale.  This climate is classified as Mediterranean, mild with warm, dry summers.

http://people.eng.unimelb.edu.au/mpeel/Koppen/North_America.jpg

This climagraph reflects the warm, dry summers and cool, wetter winters occurring in Portland's Mediterranean Csb climate.

Data source: http://www.usclimatedata.com/climate.php?location=USOR0275

Works Cited:

www.census.gov

http://www.physicalgeography.net/fundamentals/7v.html