Here is a new addition to my collection of weather URLs: http://earth.nullschool.net/
I read about it at http://www.universetoday.com. It is a javascript-driven, apparently very fluid, display of wind direction anywhere on Earth, with data updated from various models every 3 hours. There is also the ability to look back in time and to look forwards by up to 24 hours. The "earth" thingo at the bottom opens up a menu from which various settings can be selected, with the "about" link providing an explanation. Settings can be stored in a URL: http://earth.nullschool.net/#current/wind/isobaric/1000hPa/orthographic=-225.44,-36.35,416 It is evident that the jetstream at about 10km (250hPa) is very different from winds at the surface. I don't understand how the jetstream makes sense in terms of what I understand about Hadley cells: https://en.wikipedia.org/wiki/Hadley_cell On a day like today in Melbourne, at the western edge of a high pressure system, I understand a significant amount of the heat we feel (predicted maximum 40C) is due to hotter than normal, very dry, air piling up in the troposphere after being transported there from the tropics. This is in addition to air arriving from the inland north. This somehow displaces air on the ground with dryer, hotter, air. If that's the case, I am not sure how it works with the jetstream winds doing something apparently unrelated (to my eyes) with the anticlockwise winds at ground level which result from the high pressure system. My other weather links are: http://www.bom.gov.au/australia/charts/synoptic_bw.shtml http://www.bom.gov.au/vic/forecasts/melbourne.shtml http://www.bom.gov.au/vic/observations/melbourne.shtml http://www.bom.gov.au/products/IDR023.loop.shtml?looping=1&reloaded=0&topography=true&locations=true&range=true#skip http://www.bom.gov.au/australia/satellite/ http://www.bom.gov.au/jsp/watl/weather/obs.jsp?graph=all_obs&station=86068 The last one is for the nearby Viewbank weather station. This shows the last few days of temperature and other measurements, including the dew point. The dew point is a measure of the moisture content of the air. When this drops suddenly, as it did a few hours ago, I understand (from an explanation by a meteorologist) this is the dry Hadley cycle air descending to ground level and somehow (I have no idea how) displacing the more moist air which was previously at ground level. A final link, which is only for the Melbourne area is: http://www.baywx.com.au/melbtemp.html This page, one of several, shows the predicted minimum and maximum temperatures with the observations filled in as the day progresses. There's an archive of the graphs, which enabled me to generate temperature graphs of the heatwave associated with the 2009 bushfires: https://en.wikipedia.org/wiki/Black_Saturday_bushfires https://commons.wikimedia.org/wiki/File:Melbourne-temp-2009-02-10.png https://commons.wikimedia.org/wiki/File:Melbourne-temp-2009-02-10-compact.png I understand those dramatic peaks in temperature are driven largely by Hadley cells. - Robin _______________________________________________ Link mailing list [email protected] http://mailman.anu.edu.au/mailman/listinfo/link
