NOAA Releases the “State of the Climate Report” for 2009

The first observation I’d make is that the report focuses on unusual or anomalous events. It tries to put them in historical context. For example, I learned that the U.S. had the wettest October since records were collected 115 years ago. And Toronto had a snow-free November for the first time in recorded history. In all data analysis – weather data, financial data, or performance data – it is important to pull out the significant events from the rest of the data, or the “noise” as we say. NOAA does this by comparing the past year’s data with their historical data to find out where the year stood in comparison to all the other years. Similar analysis can be done by other agencies whether the metric is road-miles constructed or the percent of students receiving student aid that graduated. What is key is comparing the results in light of the historical data and trying to gain insights on what the trend is and what it means.

Because 2009 was the end of the decade, they have also compiled some data at the decade level rather than at the year level. While the 2009 average global temperature was the fifth warmest year on record, the 2000-2009 decade was the warmest on record for the globe. And the decade before, 1990 – 1999, was the warmest on record at that time. The use of multi-year averages is a good example of smoothing that can be done to help ferret out significant information and remove the year-to-year fluctuation in large collections of time series data.

The State of the Climate report shows good examples of many data analysis techniques including historical analysis, near-real time reporting, reanalysis of past data using newer, improved techniques, averaging
of multiple datasets to improve reliability, and drill down capabilities from decades, to years, to seasons, to months, and from global to regional to country and state. They also use interesting visualization techniques.