{"action":"created","issue":{"url":"https://api.github.com/repos/StrikeNP/trac_test/issues/382","repository_url":"https://api.github.com/repos/StrikeNP/trac_test","labels_url":"https://api.github.com/repos/StrikeNP/trac_test/issues/382/labels{/name}","comments_url":"https://api.github.com/repos/StrikeNP/trac_test/issues/382/comments","events_url":"https://api.github.com/repos/StrikeNP/trac_test/issues/382/events","html_url":"https://github.com/StrikeNP/trac_test/issues/382","id":332175584,"node_id":"MDU6SXNzdWUzMzIxNzU1ODQ=","number":382,"title":"Latin hypercube: CLUBB's variance of total water is too large (Trac #382)","user":{"login":"StrikeNP","id":2577059,"node_id":"MDQ6VXNlcjI1NzcwNTk=","avatar_url":"https://avatars0.githubusercontent.com/u/2577059?v=4","gravatar_id":"","url":"https://api.github.com/users/StrikeNP","html_url":"https://github.com/StrikeNP","followers_url":"https://api.github.com/users/StrikeNP/followers","following_url":"https://api.github.com/users/StrikeNP/following{/other_user}","gists_url":"https://api.github.com/users/StrikeNP/gists{/gist_id}","starred_url":"https://api.github.com/users/StrikeNP/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/StrikeNP/subscriptions","organizations_url":"https://api.github.com/users/StrikeNP/orgs","repos_url":"https://api.github.com/users/StrikeNP/repos","events_url":"https://api.github.com/users/StrikeNP/events{/privacy}","received_events_url":"https://api.github.com/users/StrikeNP/received_events","type":"User","site_admin":false},"labels":[{"id":963997231,"node_id":"MDU6TGFiZWw5NjM5OTcyMzE=","url":"https://api.github.com/repos/StrikeNP/trac_test/labels/Migrated%20from%20Trac","name":"Migrated from Trac","color":"FFFFFF","default":false},{"id":963997516,"node_id":"MDU6TGFiZWw5NjM5OTc1MTY=","url":"https://api.github.com/repos/StrikeNP/trac_test/labels/clubb_src","name":"clubb_src","color":"FFFFFF","default":false},{"id":963997249,"node_id":"MDU6TGFiZWw5NjM5OTcyNDk=","url":"https://api.github.com/repos/StrikeNP/trac_test/labels/defect","name":"defect","color":"FFFFFF","default":false},{"id":963997501,"node_id":"MDU6TGFiZWw5NjM5OTc1MDE=","url":"https://api.github.com/repos/StrikeNP/trac_test/labels/dschanen@uwm.edu","name":"dschanen@uwm.edu","color":"FFFFFF","default":false}],"state":"open","locked":false,"assignee":null,"assignees":[],"milestone":{"url":"https://api.github.com/repos/StrikeNP/trac_test/milestones/8","html_url":"https://github.com/StrikeNP/trac_test/milestone/8","labels_url":"https://api.github.com/repos/StrikeNP/trac_test/milestones/8/labels","id":3423184,"node_id":"MDk6TWlsZXN0b25lMzQyMzE4NA==","number":8,"title":"Improve SILHS","description":null,"creator":{"login":"StrikeNP","id":2577059,"node_id":"MDQ6VXNlcjI1NzcwNTk=","avatar_url":"https://avatars0.githubusercontent.com/u/2577059?v=4","gravatar_id":"","url":"https://api.github.com/users/StrikeNP","html_url":"https://github.com/StrikeNP","followers_url":"https://api.github.com/users/StrikeNP/followers","following_url":"https://api.github.com/users/StrikeNP/following{/other_user}","gists_url":"https://api.github.com/users/StrikeNP/gists{/gist_id}","starred_url":"https://api.github.com/users/StrikeNP/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/StrikeNP/subscriptions","organizations_url":"https://api.github.com/users/StrikeNP/orgs","repos_url":"https://api.github.com/users/StrikeNP/repos","events_url":"https://api.github.com/users/StrikeNP/events{/privacy}","received_events_url":"https://api.github.com/users/StrikeNP/received_events","type":"User","site_admin":false},"open_issues":53,"closed_issues":28,"state":"open","created_at":"2018-06-13T20:03:15Z","updated_at":"2018-06-14T21:32:50Z","due_on":null,"closed_at":null},"comments":4,"created_at":"2018-06-13T21:43:50Z","updated_at":"2018-06-14T22:53:28Z","closed_at":null,"author_association":"OWNER","body":"**Description**\nWhen running a deep convective case like ARM 97, we discovered that the variance of total water leads to negative total water and therefore negative water vapor being feed into the microphysics for particular sample points (generally high in the atmosphere where rtm is small).  See https://github.com/larson-group/clubb/issues/105 for more details.  Since clipping the values of vapor would lead to a positive sampling bias we don't want to do that.  Therefore, we probably need to ensure that stdev_rt < rtm in the CLUBB_core code, or ensure the values we use in the latin hypercube code don't allow for negative total water samples.\n\n**Technical Spec**\nThe code in advance_clubb_core currently prevents rtp2 from being smaller than rt_tol^2^.  We want to prevent sqrt( rtp2(k) ) from being larger than rtm(k).  The logical place to do this is within advance_xp2_xpyp since it occurs after we solve for rtm, but before we solve for quantities in pdf_closure (which feeds back into the latin hypercube sampling later).\nThe model may be sensitive to how we impose this threshold, so we should look at both:\n\n```text\nclip rtp2 < rt_tol\nclip rtp2 > rtm**2\n\n```\nvs\n\n```text\nclip rtp2 > rtm**2\n\nclip rtp2 < rt_tol\n```\n\n**Tests**\nWe have to be very careful about changing thresholds like this.  This may affect clubb_standalone, but it could potentially affect WRF-CLUBB, SAM-CLUBB, et cetera.  We do check a plotgen for:\n1. CLUBB\n2. SAM-CLUBB\n3. WRF-CLUBB\nwith at least the 2 methods of clipping outlined above.\n\nThis specification might require some modification if the results change too much using either method.\n\nAttachments:\n\n\nMigrated from http://carson.math.uwm.edu/trac/clubb/ticket/382\n```json\n{\n    \"status\": \"closed\", \n    \"changetime\": \"2010-12-03T02:50:36\", \n    \"description\": \"'''Description'''\\nWhen running a deep convective case like ARM 97, we discovered that the variance of total water leads to negative total water and therefore negative water vapor being feed into the microphysics for particular sample points (generally high in the atmosphere where rtm is small).  See comment:10:ticket:105 for more details.  Since clipping the values of vapor would lead to a positive sampling bias we don't want to do that.  Therefore, we probably need to ensure that stdev_rt < rtm in the CLUBB_core code, or ensure the values we use in the latin hypercube code don't allow for negative total water samples.\\n\\n'''Technical Spec'''\\nThe code in advance_clubb_core currently prevents rtp2 from being smaller than rt_tol^2^.  We want to prevent sqrt( rtp2(k) ) from being larger than rtm(k).  The logical place to do this is within advance_xp2_xpyp since it occurs after we solve for rtm, but before we solve for quantities in pdf_closure (which feeds back into the latin hypercube sampling later).\\nThe model may be sensitive to how we impose this threshold, so we should look at both:\\n{{{\\nclip rtp2 < rt_tol\\nclip rtp2 > rtm**2\\n}}}\\nvs\\n{{{\\nclip rtp2 > rtm**2\\nclip rtp2 < rt_tol\\n}}}\\n\\n'''Tests'''\\nWe have to be very careful about changing thresholds like this.  This may affect clubb_standalone, but it could potentially affect WRF-CLUBB, SAM-CLUBB, et cetera.  We do check a plotgen for:\\n1. CLUBB\\n2. SAM-CLUBB\\n3. WRF-CLUBB\\nwith at least the 2 methods of clipping outlined above.\\n\\nThis specification might require some modification if the results change too much using either method.\", \n    \"reporter\": \"dschanen@uwm.edu\", \n    \"cc\": \"vlarson@uwm.edu\", \n    \"resolution\": \"Verified by V. Larson\", \n    \"_ts\": \"1291344636000000\", \n    \"component\": \"clubb_src\", \n    \"summary\": \"Latin hypercube: CLUBB's variance of total water is too large\", \n    \"priority\": \"major\", \n    \"keywords\": \"\", \n    \"time\": \"2010-11-18T18:18:19\", \n    \"milestone\": \"Improve SILHS\", \n    \"owner\": \"dschanen@uwm.edu\", \n    \"type\": \"defect\"\n}\n```\n"},"comment":{"url":"https://api.github.com/repos/StrikeNP/trac_test/issues/comments/397462212","html_url":"https://github.com/StrikeNP/trac_test/issues/382#issuecomment-397462212","issue_url":"https://api.github.com/repos/StrikeNP/trac_test/issues/382","id":397462212,"node_id":"MDEyOklzc3VlQ29tbWVudDM5NzQ2MjIxMg==","user":{"login":"StrikeNP","id":2577059,"node_id":"MDQ6VXNlcjI1NzcwNTk=","avatar_url":"https://avatars0.githubusercontent.com/u/2577059?v=4","gravatar_id":"","url":"https://api.github.com/users/StrikeNP","html_url":"https://github.com/StrikeNP","followers_url":"https://api.github.com/users/StrikeNP/followers","following_url":"https://api.github.com/users/StrikeNP/following{/other_user}","gists_url":"https://api.github.com/users/StrikeNP/gists{/gist_id}","starred_url":"https://api.github.com/users/StrikeNP/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/StrikeNP/subscriptions","organizations_url":"https://api.github.com/users/StrikeNP/orgs","repos_url":"https://api.github.com/users/StrikeNP/repos","events_url":"https://api.github.com/users/StrikeNP/events{/privacy}","received_events_url":"https://api.github.com/users/StrikeNP/received_events","type":"User","site_admin":false},"created_at":"2018-06-14T22:53:28Z","updated_at":"2018-06-14T22:53:28Z","author_association":"OWNER","body":"**Trac update on 2010/11/19 at 03:45**\n**vlarson@uwm.edu commented:**\n\nReplying to [comment:4 dschanen@…]:\n> Changeset r4845 adds in the code to not impose thresholds on the variance variables when we're using fixed correlations.  I still see a few print statements about rt samples being negative, but they're far less frequent and no longer mainly in the top levels of the domain.  They actually seem to be centered around z = 60 (10.5 km), but I don't see anything special about that altitude.\n\nDoes this change allow arm_97 to run to completion?\n\nDo the negative samples have the magnitude of round-off errors?   \n\n"}}
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