GLIMS Update: Special ASTER Acquisitions for GLIMS (Gap Fill, Anniversary Pairs, Low-Saturation Plans)
Dear all, We are now over one decade into the GLIMS acquisitions by ASTER. There has been mixed success and failure of the plans, and I have never been given a really clear explanation for why some areas (including my own area in Alaska) are perennially cheated of images. Exclusion Zones related to what of importance is downrange or uprange on the orbit tracks explains a little but is ultimately not a very satisfying excuse. This is brought up every year, often twice a year at ASTER Science Team meetings, and it will be brought up again in 4 weeks. So we will continue with the GLIMS STARs but I want to add three special one-year-only acquisition plans (addenda, not replacement of GLIMS STARS), GLIMS Gap Fill Plan, GLIMS Anniversary Pair Plan, GLIMS Low Saturation Plan. I need Regional Center input for both. It is definitely a case of "the squeaky wheel gets the oil." I won't place an arbitrary limit on the number of scenes needed, but ASTER Mission Ops would probably reject a plan that involves more than 900 scenes (300 in each plan); so that is a rough target, but not a quota. I need an Excel file or a tab-delimited plain text file from each regional center for these special acquisitions. Each Regional Center interested in participating should provide one file for Gap Fill Plan, and another for Anniversary Pair Plan. This will be a proposal at the next next ASTER Science Team meeting in 4 weeks. I need the Excel files by December 20, 2011. Please reply using this message and attach your Excel files (described below). In general, if we have plans coming in from 20 regional centers, we will be able to take in 15 scene requests under each of the 3 plans for each regional center (average). Don't consider this a quota; Greenland will need more, for instance, and New Zealand fewer. We're looking for high priority targets, not complete recoverage of glaciers. The GLIMS STARs will be same or similar to last year unless noise is made to change it. (I can't forcibly address lack of 100% fulfillment, but I will rattle my cage again.) The proposal will allocate a reasonable number of images to the responding regional centers, and any perceived unused reasonable number will be where I want to place them. If you want all of what you feel is a fair allotment of coverage to be in Gap Fill or any other plan, feel free. The hope is that each regional center will get about 50 or 60 great news scenes, on average, above what the GLIMS STAR and Global Mapping STAR has been providing. One year only. GLIMS Gap Fill: Defined as an area where there does not yet exist a single adequate image over the lifetime of ASTER. This can mean that images were acquired, but all of them were excessively cloudy, or gain settings are wrong and the image was too saturated or too dark, or the scene was heavily snow-covered, or otherwise it can be imaged much better than it was (or none were ever acquired) and not a single scene yet exists that is satisfactory. This is not an program to get duplicate images. Duplicate imaging comes in the next special acquisition described below. Each solicited area should be an ASTER scene-size or smaller than ASTER scene, or if it is a bigger polygon then you should estimate the number of ASTER scenes to capture that area. Information (data columns) for each scene is:1, REQUIRED: Center latitude. This is the target location or a place close to the area of interest fitting within a 60x60km area (where you want gain settings calculated). Could be from Google Earth.2, REQUIRED: center longitude. Target location. Could be from Google Earth.3, REQUIRED: Geographic place. One to several word text comment giving a geographic name or description of the target4, REQUIRED: Start date. Start of ASTER image acquisition window (DD/MM/YY format)5, REQUIRED: Stop date. End of acquisition period. (DD/MM/YY format)6, OPTIONAL: A previous ASTER image acquisition scene identifier. 7, OPTIONAL: Comment. Can be "dark lake imaging," or "rock debris imaging," or "snowy surface imaging," or any comment to distinguish this planned target from typical glacier ice. Or any other comment.8, OPTIONAL: email address of 1 responsible person GLIMS Anniversary Pair Plan: Intent is to get another image in a 2-time (or more) series acquired under the same gain settings and near an anniversary date, with low cloud cover and low snow cover.Information for each scene (note differences from Gap Fill):1, REQUIRED: Center latitude. Could be from Google Earth.2, REQUIRED: Center longitude. Could be from Google Earth.3, REQUIRED: Geographic place. One to several word comment giving a geographic name or description of the target4, REQUIRED: Previous ASTER. This is a previous ASTER image acquisition scene identifier. This will be used to match gain settings and date of acquisition. 5, Optional: Email address of 1 responsible personIn general, the target dates will be the same as the within +-8 days for low latitude targets grading to +-2 days for high latitude targets. A default value of 1 scene will be imposed, so don't specify large polygons. These requests need to be tied to specific prior individual images so we can seek to replicate the acquisition. GLIMS Low Saturation Plan: Intent is to try again with something from a few years that Mission Ops said they approved but never implemented: Gain settings will be systematically shifted from nominal GLIMS gains to allow acquisition of imagery with lower saturation. This will be calculated in general with the GLIMS STAR gain calculator by assuming slopes that are 15 degrees equatorward (for non-tropics, this effectively is like reducing the latitude inputs by 15 degrees, thus allowing steeper sunward slopes or snowier surfaces to be unsaturated). Information:1, REQUIRED: Center latitude. This is the target location or a place close to the area of interest fitting within a 60x60km area (where you want gain settings calculated). Could be from Google Earth.2, REQUIRED: center longitude. Target location. Could be from Google Earth.3, REQUIRED: Geographic place. One to several word text comment giving a geographic name or description of the target4, REQUIRED: Start date. Start of ASTER image acquisition window (DD/MM/YY format)5, REQUIRED: Stop date. End of acquisition period. (DD/MM/YY format)6, OPTIONAL: A previous ASTER image acquisition scene identifier. 7, OPTIONAL: Comment. Can be "Use 25 degree slope," for example, in the Himalaya where common slopes may be much, much steeper than 15 degrees. Or any comment.8, OPTIONAL: email address of 1 responsible person --Jeff Kargel
Dear all, Rick Wessels has suggested that having a well-defined list of proposed image acquisitions for the three supplemental GLIMS acquisition requests prior to Dec. 9 (prior to start of the ASTER Science Team meeting) would be helpful. I understand that this is a big analysis job for people, and with Fall AGU and Thanksgiving holidays approaching for Americans, I must allow a December 20 deadline just for calendar realism. However, if you can meet a Dec. 9 pre-deadline, that would help a lot, exactly for reasons Rick summarized to me. This can be one discussion topic at the Fall AGU meeting (our gathering date still TBD... anybody have suggestions?) It might be highly informal, just a mob of people in my hotel room, with pizza and beer; unless too many people plan to attend, in which case we will go to a restaurant. (NOT the Chinese restaurant with the fast-talking, number-crunching, bill-rearranging, and mind-breaking owner we had a few years ago for those of you who were there!) --Jeff Kargel From: jeffreyskargel@hotmail.com To: glims@nsidc.org Subject: GLIMS Update: Special ASTER Acquisitions for GLIMS (Gap Fill, Anniversary Pairs, Low-Saturation Plans) Date: Thu, 10 Nov 2011 22:22:20 +0000 Dear all, We are now over one decade into the GLIMS acquisitions by ASTER. There has been mixed success and failure of the plans, and I have never been given a really clear explanation for why some areas (including my own area in Alaska) are perennially cheated of images. Exclusion Zones related to what of importance is downrange or uprange on the orbit tracks explains a little but is ultimately not a very satisfying excuse. This is brought up every year, often twice a year at ASTER Science Team meetings, and it will be brought up again in 4 weeks. So we will continue with the GLIMS STARs but I want to add three special one-year-only acquisition plans (addenda, not replacement of GLIMS STARS), GLIMS Gap Fill Plan, GLIMS Anniversary Pair Plan, GLIMS Low Saturation Plan. I need Regional Center input for both. It is definitely a case of "the squeaky wheel gets the oil." I won't place an arbitrary limit on the number of scenes needed, but ASTER Mission Ops would probably reject a plan that involves more than 900 scenes (300 in each plan); so that is a rough target, but not a quota. I need an Excel file or a tab-delimited plain text file from each regional center for these special acquisitions. Each Regional Center interested in participating should provide one file for Gap Fill Plan, and another for Anniversary Pair Plan. This will be a proposal at the next next ASTER Science Team meeting in 4 weeks. I need the Excel files by December 20, 2011. Please reply using this message and attach your Excel files (described below). In general, if we have plans coming in from 20 regional centers, we will be able to take in 15 scene requests under each of the 3 plans for each regional center (average). Don't consider this a quota; Greenland will need more, for instance, and New Zealand fewer. We're looking for high priority targets, not complete recoverage of glaciers. The GLIMS STARs will be same or similar to last year unless noise is made to change it. (I can't forcibly address lack of 100% fulfillment, but I will rattle my cage again.) The proposal will allocate a reasonable number of images to the responding regional centers, and any perceived unused reasonable number will be where I want to place them. If you want all of what you feel is a fair allotment of coverage to be in Gap Fill or any other plan, feel free. The hope is that each regional center will get about 50 or 60 great news scenes, on average, above what the GLIMS STAR and Global Mapping STAR has been providing. One year only. GLIMS Gap Fill: Defined as an area where there does not yet exist a single adequate image over the lifetime of ASTER. This can mean that images were acquired, but all of them were excessively cloudy, or gain settings are wrong and the image was too saturated or too dark, or the scene was heavily snow-covered, or otherwise it can be imaged much better than it was (or none were ever acquired) and not a single scene yet exists that is satisfactory. This is not an program to get duplicate images. Duplicate imaging comes in the next special acquisition described below. Each solicited area should be an ASTER scene-size or smaller than ASTER scene, or if it is a bigger polygon then you should estimate the number of ASTER scenes to capture that area. Information (data columns) for each scene is:1, REQUIRED: Center latitude. This is the target location or a place close to the area of interest fitting within a 60x60km area (where you want gain settings calculated). Could be from Google Earth.2, REQUIRED: center longitude. Target location. Could be from Google Earth.3, REQUIRED: Geographic place. One to several word text comment giving a geographic name or description of the target4, REQUIRED: Start date. Start of ASTER image acquisition window (DD/MM/YY format)5, REQUIRED: Stop date. End of acquisition period. (DD/MM/YY format)6, OPTIONAL: A previous ASTER image acquisition scene identifier. 7, OPTIONAL: Comment. Can be "dark lake imaging," or "rock debris imaging," or "snowy surface imaging," or any comment to distinguish this planned target from typical glacier ice. Or any other comment.8, OPTIONAL: email address of 1 responsible person GLIMS Anniversary Pair Plan: Intent is to get another image in a 2-time (or more) series acquired under the same gain settings and near an anniversary date, with low cloud cover and low snow cover.Information for each scene (note differences from Gap Fill):1, REQUIRED: Center latitude. Could be from Google Earth.2, REQUIRED: Center longitude. Could be from Google Earth.3, REQUIRED: Geographic place. One to several word comment giving a geographic name or description of the target4, REQUIRED: Previous ASTER. This is a previous ASTER image acquisition scene identifier. This will be used to match gain settings and date of acquisition. 5, Optional: Email address of 1 responsible personIn general, the target dates will be the same as the within +-8 days for low latitude targets grading to +-2 days for high latitude targets. A default value of 1 scene will be imposed, so don't specify large polygons. These requests need to be tied to specific prior individual images so we can seek to replicate the acquisition. GLIMS Low Saturation Plan: Intent is to try again with something from a few years that Mission Ops said they approved but never implemented: Gain settings will be systematically shifted from nominal GLIMS gains to allow acquisition of imagery with lower saturation. This will be calculated in general with the GLIMS STAR gain calculator by assuming slopes that are 15 degrees equatorward (for non-tropics, this effectively is like reducing the latitude inputs by 15 degrees, thus allowing steeper sunward slopes or snowier surfaces to be unsaturated). Information:1, REQUIRED: Center latitude. This is the target location or a place close to the area of interest fitting within a 60x60km area (where you want gain settings calculated). Could be from Google Earth.2, REQUIRED: center longitude. Target location. Could be from Google Earth.3, REQUIRED: Geographic place. One to several word text comment giving a geographic name or description of the target4, REQUIRED: Start date. Start of ASTER image acquisition window (DD/MM/YY format)5, REQUIRED: Stop date. End of acquisition period. (DD/MM/YY format)6, OPTIONAL: A previous ASTER image acquisition scene identifier. 7, OPTIONAL: Comment. Can be "Use 25 degree slope," for example, in the Himalaya where common slopes may be much, much steeper than 15 degrees. Or any comment.8, OPTIONAL: email address of 1 responsible person --Jeff Kargel
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Jeffrey Kargel