California Climate, PDO, LOD, and Sunspot Departure

Above: Length of Day Compared to Global Temperature since 1890

Below is a paper by former California State Climatologist, Jim Goodridge. Jim  has been quietly working on a  number of rainfall and climate projects both for himself, and as a consultant for the California Department of Water Resources.

In this essay, Jim looks at many factors that can be linked to California’s climate. and also into something that hasn’t gotten a lot of discussion - Length of Day. It seems there may be some correlation to surface temperatures and the Pacific Decadal Oscillation. Jim also has looked at accumulated departure of solar irradiance and of sunspot numbers.

I present his essay here without comment, for the purpose of discussion. My only contribution, just for the sake of curiosity, was to provide the graph above that compares Length of Day to Global Temperature for the last 100 years.

For those that wish to distribute this essay, here is a link to it in Adobe Acrobat PDF form:

Persistence in California Weather - J. Goodridge (PDF 893k)

 

Persistence in California Weather Patterns

Jim Goodridge

 State Climatologist (Retired)

jdgoodridge@sbcglobal.net

 

Summary:

The evidence for a major climate shift since the mid 1970s is quite real.  California indices of rainfall and temperature have both shown an increasing trend since 1975.

Physical changes in Earth weather systems that accompany the 1975 weather trend changes include the Pacific Decadal Oscillation (PDO) index, a 1975 change in the Atmospheric Angular Momentum (AAM) index and a 1940 increase in solar irradiance.

The PDO index is a measure of the East West sea surface temperature difference in the North Pacific Ocean. The AAM index is a measure of the ratio of East West vs. North-South winds on the planet that affect the earth rotation rate.

Solar irradiance has been monitored from satellites for three sunspot cycles. The sunspot numbers and solar irradiance were shown to be highly correlated. Since sunspot numbers have been increasing since 1940 the irradiance must also be increasing.