Back to main menu    /    d1+12Z     /    d2+12Z     /    Help and usage    /   Use the clickable blipmaps below to get the name (mouse over) or the profile (click on) of a location (black small star).
sound12alpsj201.png sound12alpsj202.png sound12alpsj203.png sound12alpsj204.png sound12alpsj205.png sound12alpsj206.png sound12alpsj207.png sound12alpsj208.png sound12alpsj209.png sound12alpsj210.png sound12alpsj211.png sound12alpsj212.png sound12alpsj213.png sound12alpsj214.png sound12alpsj215.png sound12alpsj216.png sound12alpsj217.png sound12alpsj218.png sound12alpsj219.png sound12alpsj220.png sound12alpsj221.png sound12alpsj222.png sound12alpsj223.png sound12alpsj224.png sound12alpsj225.png sound12alpsj226.png sound12alpsj227.png sound12alpsj228.png sound12alpsj229.png sound12alpsj230.png sound12alpsj231.png sound12alpsj232.png sound12alpsj233.png sound12alpsj234.png sound12alpsj235.png sound12alpsj236.png sound12alpsj237.png sound12alpsj238.png sound12alpsj239.png sound12alpsj240.png sound12alpsj241.png sound12alpsj242.png sound12alpsj243.png sound12alpsj244.png sound12alpsj245.png sound12alpsj246.png sound12alpsj247.png sound12alpsj248.png sound12alpsj249.png sound12alpsj250.png sound12alpsj251.png sound12alpsj252.png sound12alpsj253.png sound12alpsj254.png sound12alpsj255.png sound12alpsj256.png sound12alpsj257.png sound12alpsj258.png sound12alpsj259.png sound12alpsj260.png sound12alpsj261.png sound12alpsj262.png sound12alpsj263.png sound12alpsj264.png sound12alpsj265.png sound12alpsj266.png sound12alpsj267.png sound12alpsj268.png sound12alpsj269.png sound12alpsj270.png sound12alpsj271.png sound12alpsj272.png sound12alpsj273.png sound12alpsj274.png sound12alpsj275.png sound12alpsj276.png sound12alpsj277.png sound12alpsj278.png sound12alpsj279.png sound12alpsj280.png sound12alpsj281.png sound12alpsj282.png sound12alpsj283.png sound12alpsj284.png sound12alpsj285.png sound12alpsj286.png sound12alpsj287.png sound12alpsj288.png sound12alpsj289.png sound12alpsj290.png sound12alpsj291.png sound12alpsj292.png sound12alpsj293.png sound12alpsj294.png sound12alpsj295.png sound12alpsj296.png
Surface parameters: mslp / sfc temperature / sfc dew point / sunshine / snow cover   /  Wind parameters  /  thermal parameters  /  clouds parameters
Quick help: This macroscale snow cover chart is showed in order to explain (warn) a potential limitation of RASP. Purple areas mean the ground surface is simply covered with snow without taking account of the thickness of snow. Blue areas mean region without snow. The forecast problem can be traced to input from the driving global GFS model, with too large snow region over the mountains at macroscale (GFS model view). Naturally if RASP is told there is snow cover it is going to under-evaluate BL, ground heating and thermals, and other predictions which depend upon surface heating will also be incorrect. The probable reason for the anomalously-and too coarsely predicted snow is that GFS uses "envelope topography" which for terrain values uses the maximum elevation in a grid cell, which would produce a large area of higher-than-actual elevations and hence more snow than is actually the case. Because the grid cell of macroscale GFS is around 50km, any such anomaly is spread over many points in the RASP grid. It is an example of a case in which RASP forecasts can be invalid due to its dependence upon forecasts from the global model. To alleviate this anomaly I "tell" to my Alps RASP model before it runs that there no snow in winter and in the beginning of spring when there has been no new snow fall for a few day, because in this case I empirically notice that probably the heating effect of snow-free alpine pine forest is not negligible in the alpine valley.
Aide rapide: Cette carte de la couverture neigeuse montre les zones o la prvision des thermiques peut tre sous-estime. Les aires violettes signifient que RASP considre qu'elles sont couvertes de neige (quelque soit l'paisseur du manteau neigeux) alors que les aires bleues (ou grises si absence totale de neige sur tout le domaine) sont considres comme libre de neige. Ceci est d au fait que RASP n'est pas encore capable de calculer la couverture neigeuse en fonction de son relief ou du relief rel. Il fait donc ses calculs en prenant compte la couverture neigeuse du modle de base macrochelle (GFS) qui ne "voit" que grossirement celle-ci. Par exemple les valles profondes (non vues par GFS) dans une zone violette sont considres comme couvertes de neige alors qu'en ralit elles ne le sont souvent pas. Pour pallier cette anomalie, je dclenche dans le programme la prise en compte de la couverture nuageuse, lorsque j'observe peu de neige, notamment sur les forts de conifres, dans les valles, en particulier la fin de l'hiver et au dbut du printemps.