Dear All, My view on this is that I would include sea ice as 'honorary land' when it comes to skin temperatures on the basis that both are solid rather than liquid, which fits in with Nathan's suggestion of having the new term cover any skin temperatures that aren't measured on liquid water.
Cheers, Roy. ________________________________ From: CF-metadata [[email protected]] On Behalf Of Evan Manning [[email protected]] Sent: 30 June 2013 16:10 To: [email protected] Subject: Re: [CF-metadata] new standard name: land_surface_skin_temperature Now we'll have sea_surface_skin_temperature and land_surface_skin_temperature. Will we also add an ice_surface_skin_temperature? This raises issues of what the land & sea surface skin temperatures are when there is ice or snow over the dirt or ocean. Is it the temperature where land meets ice or where ice meets air? >From my perspective with AIRS, looking down through the atmosphere at the Earth, the answer is clearly that we sense the surface at the bottom of the atmosphere, whether it is land, ice/snow, water, or some combination of those. I'd like us to have a "surface_skin_temperature" and use "area_fraction"-family fields to tell users what portion of the observed area is frozen or what portion is liquid. This mirrors what we currently do in non-CF HDF products. I don't object to also having "sea_surface_skin_temperature" etc. Presumably with an observation of an extended area where part is land and part is sea, the sea_surface_skin_temperature would be the temperature of the part that is sea. If part of the sea portion is covered in ice, would that part be included in the sea_surface_skin_temperature? Ditto land? -- Evan On Fri, Jun 14, 2013 at 11:45 AM, <[email protected]<mailto:[email protected]>> wrote: Thanks for your comments. They all make sense to me and I'm on board with your suggested definition. I'll just wait for others to comment, if needed, then we can converge on a final definition. Sincerely, Jonathan On 6/14/2013 2:11 PM, Jim Biard wrote: Jonathan, I still don't believe that the surface temperature concept that Jonathan Gregory has ever been what people were intending when they make the surface_temperature standard name, but I'll abide by whatever folks decide. On a different front, I don't think the definition of the standard name should include statements about technology used (measured by an infrared radiometer…). The definition should speak only to the measured quantity, without reference to the way in which you happen to be measuring it. Likewise, there is no need for the statement regarding variability of the quantity. Also, the surface in this name is not the lower boundary of the atmosphere. It is the upper boundary of the land. An non-volatile object in a hard vacuum has a surface skin temperature. Given all that, I'd suggest this for your definition: Standard Name: land_surface_skin_temperature Definition: The land surface skin temperature is the aggregate temperature of the "skin" of the land surface, which extends vertically approximately 12 micrometers below the land surface. If people really think it needs to be spelled out even further, add the sentence "The land surface is the upper boundary of the land." Grace and peace, Jim ________________________________ This message (and any attachments) is for the recipient only. NERC is subject to the Freedom of Information Act 2000 and the contents of this email and any reply you make may be disclosed by NERC unless it is exempt from release under the Act. Any material supplied to NERC may be stored in an electronic records management system.
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