How to access Copernicus sea surface temperature data

hello and welcome to you met search my name is Mark Higgins in this series of videos we're going to be walking through how you can discover download manipulate and visualize some of the amazing copernicus sentinel 3 data in the following videos we're going to introduce you to some of the you met SAP product experts they're going to walk you through how you use some of the free and open tools like Bratz snap and QGIS to really get under the skin of these data to manipulate it and visualize it we really hope that you will enjoy and use this data in your work or your curiosity about the earth and marine environment welcome to you mats that my name is Anna Carol and I'm going to give you an overview of sea surface temperature products from Sentinel 3 you may have already seen the previous episodes from mark on coda and on ocean color from Haley today I'm going to give you an overview of sea surface temperature products from the sea and land surface temperature radiometer these are at 1 kilometre pixel resolution and I'm going to give you an idea of how to download understand and visualize these data so now we're going to download sea surface temperature data from the Copernicus online data access so first of all you go to code or you Mets at door int and then you move to your region of interest for more details on how to do the data selection you can look at the previous episode where mark Higgins showed you how to download the data so I'm going to detailed search for SL ser the data I'm looking at level 2 products of sea surface temperature and I'm going to look for data from the 19th of September I'd like to select this product here over Florida once you've selected the product that you want and you can download it and save it so once we've got that ready on my desktop I can use the Sentinel 3 application platform for visualizing the data so I'd like to open the sea surface temperature product for this one you do it a little bit differently than for other Sentinel 3 products so you go into the directory the safe directory itself and you open at the netcdf product you can see that you come up now with a product with a lots of different bands and I'll go through some of these bands and explain to you what they mean so the main variable for this product is the sea surface Britta this is a skin at sea surface temperatures as measured by the satellite so this is for the Florida region it's a night time image so in snap you visualize it upside down so the first thing I'm going to do is just rotate it okay so we'd like to apply a color scale the way that you do this is you go to view two windows and select color manipulation you can choose whatever color palette you like and then what you'll need to do is just to adjust the thresholds so that you get some nice features coming out in the sea surface temperature so we'll just play around with that a little bit until it looks good okay another thing that it's nice to do is we like to look at the actual values of the sea surface temperature so you can do that by again by going to tour windows and selecting the pixel info and then as you move your cursor around the screen you can see the different temperatures there we can see that's 302 kelvins and then as we graduate across the Gulf of Mexico we can see how it's varying what we do need to do is look at the different quality levels in the data so you can see here that those temperatures over the whole image and this is one kilometer data but this is actually a cloud where you see the cooler temperatures so what we'd like to do is use the quality level to select only the sea surface temperature pixels so the way that we do that is we go back to the product Explorer and we go to the mask manager into Windows we can select a variable what we'd like to do is to select a quality level and in this data product we have quality levels ranging from zero to five so quality levels three to five are the best quality and observations so we'd like to mask out the quality levels that are zero one and two so we do that point by putting a minimum value of zero and a max value of two you click OK and then you can choose the color so I'm going to just assign that to black and transparency will be zero so now we have the sea surface temperature image over Florida and we've masked out in black the cloud and you can see the land is also masked out there as well so the next thing I'm going to do is just take you through some of these the meaning of these variables so the important ones that you'll need to know are the s STD time so this is time difference from a reference field in the netcdf file I've already shown you how quality level works so in selecting quality levels three in a above for the best quality SST data we have latitude and longitude because this is an image that's projected at one kilometer resolution and we also have a variable called LTP flags and I'll just show this in the flag coatings so this gives you information on the on the pics also it tells you whether the pixels over land or ocean whether there's ice in the field of view it also gives you information on whether the pixel is in daytime it's got some cloud information on this so this flag really helps you to interpret the data now the sea surface temperature product from Sentinel 3 is in what we call the Grist specification so this is the group for high resolution sea surface temperature this is kind of an international we're all SST producers from over the world tried to produce their SST in the same specification so just show you this on the webpage this is the webpage the group for high resolution sea surface temperature there's lots of information on this webpage you can find more this is a collaboration where a common specification is used to distribute sea surface temperature data and then this also creates a common framework for data sharing and through a data distribution as well so this means that I can explain to you their fields that are needed to comply with this grist a specified field the next thing that's important are information on the uncertainties and the errors and the main way that this is stored in the grist product is through the sses bias and the SSIS standard deviation this is the sense of specific error statistics so I'll just open these fields and show you and I won't rotate them but you can see here from the bias field that we have sort of different values here to here and if we look at the pixel information you can see what the values are so for the bias here we can see actually zero bias over this part of the swath and - naught point naught six over this part so when you take your sea surface temperature data from the product you should apply yes SAS bias before you can use the SST values one interesting thing to note from this image is you can see how the STR instrument works so it's a jaw view instrument with two views to the surface but the dual part of the swath is only in this Center around seven hundred forty kilometers with over this part of the swath and this part of the swath we only have a nadir only SST retrievals this is a single view through the atmosphere and this is why you can see some differences in the bias again when we look at this don't a deviation we can see the same thing there's different values over the door for you part of the swath to the nadir view only part of this swath so that just gives you some information on how to interpret your SST our data okay so I've just shown you sea surface temperature the bias and the standard deviation the quality level in the flags these are the main variables that you will need to use your sea surface temperature data now the grease specification also has some other fields included and these are really to help within SST applications and how you use your data and examples are wind speed so I'll put that one so this comes from ECMWF so this is a model wind speed and this can help you to interpret your SST data you can look for occurrences of diurnal variations you can understand the skin effect and the surface layer through the surface of the ocean and it can really help you to understand your SST data a bit better there are some other variables as well as sea ice fraction I won't share it in in this region but that can be very useful towards that the ice edges you may need to use that one as well and there's also a variable called aerosol dynamic indicator assist yeah because of its jaw view has a very good capability for coping with aerosol in the atmosphere and detecting SST but it may be affected a bit so you can check for aerosol dynamic at indicator and this can help you to interpret your SST data so I've given you a summary sea surface temperature products from Sentinel 3 from the sea and land surface temperature radiometer and these are supplied in the greased specification the group for high-resolution sea surface temperature the common specification used worldwide so I'd like to thank you for watching this episode and you can refer back to the previous episodes on coder and ocean color and keep updated for future episodes of future central 3 marine products and further information that will be coming

Channel: EUMETSAT

Views: 10,494

Keywords: EUMETSAT, Meteorology, Weather, Climate, Europe, Meteosat, Metop, Copernicus, SST

Id: lKyUeN3uS0Q

Length: 11min 1sec (661 seconds)

Published: Wed Nov 01 2017