Snow Science Friday - One Data Point Is Not a Trend

One snowfall data point does not undermine climate change science. But, put a few of them together, and pretty soon a pattern on climate variability emerges.

Two big snow storms in one season, and the aggravation of coping with endless mounds of snow creates strong emotional reactions, but not much science.

So come in from the cold, grab a cup of coffee and let's see what we can learn about the real trends and patterns of snowfall in our region.

The most readily available long-term data sets in our region is from the Chantilly, VA (Dulles airport IAD), Washington DC and Baltimore MD weather stations. So let's start with the Dulles IAD data.

First cut - (Charts 1 & 2) looking at annual snowfall totals from 1963 through the 2009-2010 current season, a couple on interesting stats emerge.

The linear trend in annual snowfall totals is actually declining at almost 1/10 of an inch per year. And quite noticeable is the three extra ordinary snow seasons of '95-96, '02-03 and the still accumulating '09-10.

Chart 1 - Dulles Snowfall 1963-2010 - Trend Analysis

Chart 2 - Dulles Snowfall Scatterplot with Linear Regression Fit

Next, let's take a longer view. The following chart (Chart3) looks at the combined average annual snowfall at three Metro DC weather stations in Chantilly (Dulles), Washington DC and Baltimore. The advantage here is that the weather data is available all the way back to 1883 in Baltimore.

The larger data set shows a similar linear trend line. Considering all the data, this trend analysis also shows a declining trend in annual snowfall. Sort of counter-intuitive when your digging out from another major snowfall. That's part of the message here ... be careful basing your judgement of the world around you, on the last data point.

Table 3 - Metro DC Average Annual Snowfall 1883-2009

Finally, (Chart 4) here's a different view of the Dulles data. Using control charts for the individual year totals and year-to-year range of change in annual snowfall data, looking at the central lines, we see can see both the declining annual snowfall average, the increasing range (variability) of annual snowfall. Note that our recent snowfalls have hit the upper control limits of the Individuals and Moving Range Charts - indicating the occurrence of a high magnitude and very low probability event. Another takeaway - for the last three decades - 1980's, 1990's and 2000's - we have seen a noticeable increase in year-to-year variation in total snowfall.

Chart 4 - Control Chart (Indivd. & mR) Annual Snowfall - by decade Dulles (IAD) - 1963-2010

So after all the r-winger emotional buzz about big snowfalls under-cutting Climate Change Science, this fast-pass data crunch of local snowfall data, says that annual snowfall is trending down and increasingly becoming highly variable. Whether it's our local micro-climate variation, or the larger global weather patterns -- you can't miss the increased variability of weather in our modern times.

Climate Change is about much more than the Global Warming and Polar Ice Melt. Thinking statistically - the increasing variability in magnitude of Hurricanes, Floods and Snow Storms are all part of our Global Climate Change reality.

Climate change denialists will not be swayed, and will likely resist any meaningful corrective actions, so I say "fuhget about 'em". For those of us that choose science over magical thinking, this is more evidence of the wild times ahead due to our inability to rein in our impact on the global climate.

Best advice here ... fore-warned is fore-armed. Be Prepared.

data source: NWS - NOAA

2/15 UPDATE: [Related story on NPR] Get This: Warming Planet Can Mean More Snow

2/18 UPDATE: Nice to have a NYT columnist agree with me

Manufacturing Monday - Caveat Emptor, Made in China

MADE IN CHINA

Buyer beware. A familiar concern returns. Products made in China can be hazardous to your health. This systemic pattern of data, does not bode well for China.

Melamine: Product adulteration... again in China - Reuters

With a renewed regulatory vigor, expect the FDA to ramp up surveillance of medical products and pharmaceuticals. The Bush Administration, took a laissez faire attitude in fundamentally reducing the oversight role of government in business, resulting in severely reduced FDA enforcement resources. The Obama Administration will likely ramp up much needed scrutiny of China's bad manufacturing practices. Process and product quality data will lead to corrective and preventive actions. China will probably continue severe punishment for those responsible, but systemic reform will take much longer.

Well beyond regulated products, Quality and Engineering professionals generally regard Chinese Manufacturing as risky business. Labor cost are very low, but often, so is product quality and safety. Companies concerned about intellectual property rights and intentional fraud in compliance to product specifications, are increasingly looking outside of China to reduce risk to their supply chains. The tendency to cut quality control corners, substitute off-spec raw materials (see Melamine and Heparin incidents), and intentionally circumvent design specifications, all purely for profit motives; is an endemic problem that reaches well beyond the more well-known problem of music and video piracy.

Confronting China's Quality Gap - Business Week

Consumers and US corporations alike, are reconsidering the risk of products, Made in China.