It is Climate Week Theme for your word of the day. That means that all words this week will deal with climate indices or climate processes. Remember that these patterns influence weather patterns over a larger time frame in general, and not just for a few days. It is impossible to cover all of the terms in just 7 days, but we hope to hit the highlights on some things climate related. Today we will talk about PDO. The PDO stands for Pacific Decadal Oscillation and refers to the Pacific Ocean north of 20N, just like with ENSO there is a positive and negative phase to the PDO. A positive phase of the -PDO results in the western portion of the north Pacific being cooler than average and areas right along the coast of North America being warmer than average. In an negative phase of the PDO this is reversed. The impacts of a positive PDO are similar to an El Nino with above average temperatures across the Canada and the Pacific Northwest and below average temperatures and above average precipitation across Mexico and the southern USA. These changes are caused by the southward shifting of a low pressure system in the Aleutians of the coast of Alaska, which influences the pattern in the jet stream. The difference that is PDO is a longer range oscillation(lasting 15 to 30 years in general, although some year to year variation is there) compared to El Nino/La Nina(which lasts from about 5 months to a maximum of a few years peaking in the winter time). That is one major difference between ENSO and the PDO That was your word of the day. It is Climate Vocabulary Week 18) AO 19) NAO 20) Greenland Block 21) PNA 22) EPO(Climate one) 23) Greenhouse Effect Next week is Karst Vocabulary Week
Posted on: Sun, 17 Aug 2014 21:49:16 +0000
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