When snow hits the ground, New Jersey's state climatologistgets calls from the morning news shows about the best packing snow conditionsand snowman fashion accessories. But David Robinson also runs an internationalsnow-cover database that includes satellite data from the past five decades.
That data on snow cover comes from the National Oceanic andAtmospheric Administration (NOAA), butRobinson cleans up the data and updates a map so that people cancomparepresent snowfallwith that of past years. Such information, hosted byRutgers University in New Jersey, endedup in the executive summary of the most recent report by the IntergovernmentalPanel on Climate Change.
LiveScience caught up with Robinson while reporting from thefall meeting of the American Geophysical Union in December to talk about all thingssnow-related.
Q: Thanks fortaking the time to talk.
A: You know, I'vedone thewhiteChristmas storiesbefore. I've actually done two interviews over my yearsas a snow scientist, although both may have come at me - I'm the stateclimatologist in New Jersey - and they may have just come from reporters on howto build a snowman.
They call,"Oh, what's the best snow, and what do yousay to do this?" I've gotten such a kick out of those,"Well, NewJersey can have good snow because it's not real powdery and it's often wetenough." One time I talked to a fashion person about how to decorate thesnowman after it was built, so I had to help them construct it ... the point isyou have to have fun with this sometimes.
Q: Right.Speaking of snow, what about all thosestrange snowfall eventswe hear about?
A: You can findsnow in some odd places at somewhat unusual times of the year, and it's afortuitous alignment of cold and moisture. It doesn't signify the coming iceage, nor is it indicative of global warming. In the short term, while it's an extreme,and climate change is likely to lead to more extremes, you know as well as I dothat one extreme doesn't cut it.
Then there's always the fact with all of these {events} thatthey may have happened before, and not all that far into the past. In this CNNworld, things get reported quickly. That biases the reporting record {towardthe present}. It snows in Miami, you're going to get tweets and blogs andeverybody's going to know. So you have to filter that these days.
Q: Does that meanwe shouldn't be surprised by these unusual weather patterns?
Interestingly enough, in the first half of November, thesnow cover in the western half of Eurasia was well below average. I wasstarting to think we were headed toward satellite record period lows, and thenthe last two weeks of the month, just ... bam! And North America was low untilmid-November, and then it just exploded. If you wait around long enough ... Ialways say the difference is that meteorologists get the instant feedback. Climatologistshave to be patient. And you can't jump to conclusions on the 15th of the monthand say,"Oh, we're going to have a record for the month," because assoon as you say that, it flips around.
Now somebody was telling me ... Phil Jones, poor Phil Jonesfrom East Anglia who made all the news {aboutClimategate}.Phil and I were talking this morning, and he said that some spot in England hadthe warmest day on record in November, last month, and the coldest day onrecord last month.
But that's the beauty of the climate system. When it getsinto a hyperactive state you go to extremes, you go from warmth to cold. Asopposed to ... you get these periods of zonal flow, where the cold stays where itbelongs and the warmth stays where it belongs. But if you get that jet streamin what we call meridional pattern - big buckles - and you can go from oneextreme {to another}. {A meridional pattern is an atmospheric system that flowsalong a meridian, or a large imaginary circle on Earth's surface that crossesboth poles.}
Syracuse {in New York} had about 66 inches of snow thismonth {December} so far. The first day of December they were 63 degrees F withtwo inches of rain. They just had an amazing month. On TV this morning, theytried to point out that it's half their winter snow and it's not even winteryet! Well, climatologically, it's winter. Syracuse gets impacted by lake-effectsnows, and lake-effect snows are most prominent when the lakes are still warmearly in the season, so it's not unusual to front-end load Syracuse's snow.
Q: Have therebeen any changes in snowfall or snow cover over the past years?
A: I've looked attrends in extent of snow cover. Fall and winter over the 45-year satelliterecord don't show a trend in snow cover (that's snow on the ground, notsnowfall). But the spring{s} of each decade, the 70s, 80s, 90s, the past decade,have had decreasing amounts of spring snow cover. In other words, fall snowsaren't coming later from what we've seen in the record in recent decades, butsnows are melting earlier starting in mid- to late winter and working their wayup.
Even last winter, North America had record extensive snowcover in February. Skeptics were out there saying,"Ooh, climate changeisn't so bad." I said,"Wait until spring." Spring had the leastamount of snow cover on record. We went from the most amount of snow to theleast amount of snow cover. For reasons yet to be fully understood ... we'restill working on whether the snow packs are thinner going into the spring,whether we're bringing warm air up into the snow-covered regions earlier, or whetherthe background is warm enough and primed, because all you need to get is to thefreezing point.
That's the neat thing about snow. It's not this linear thing- it's all about the freezing point. We had an incredibly mild winter last yearin the higher latitudes, but it was still plenty cold enough to have snow. Itwas just a little cooler in the mid-latitudes, and that was just enough to makeit snow.
Q: Have youenjoyed keeping the climate records and tracking snow cover?
A: It's beenwonderful. It's something I latched onto, and I've not been a day without sometype of research support since I was a grad student to look at it. Right now,when you go onto our website, you can find the daily product NOAA created. Butwe actually took the long-term weeklies and made a daily climatology.
So now when you go onto this website, you not only see wherethe snow is today, but I believe we're the only place in the world where youcan hit the next button and see where it's anomalously low, or how extensive orbelow average. Because you look at the map and think,"Oh well, that'sinteresting," but then you think,"Should there be snow or shouldn'tthere be snow?" I hardly ever look at the map, I go right to the anomalymap. I'm real pleased and proud of that one. So it's been fun. Like I said, yougot to have some fun with this. It's serious stuff - this is a key climateindicator, it integrates temperature, precipitation, weather patterns andextremes - but everybody loves to talk about snow.
For the latest snow-covercharts of the Northern Hemisphere, clickhere.
You can followLiveScience Senior Writer Jeremy Hsu on Twitter @ScienceHsu.
- Original Story:Q&A: The'Snowman' Talks Wild Winter Weather
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