BEGIN:VCALENDAR VERSION:2.0 PRODID:-//18.83.4.138//NONSGML kigkonsult.se iCalcreator 2.20// CALSCALE:GREGORIAN METHOD:PUBLISH X-WR-CALNAME:Oceans at MIT X-WR-CALDESC:Striving to understand\, harness and sustain Earth'\;s def ining frontier. X-FROM-URL:http://oceans.mit.edu X-WR-TIMEZONE:America/New_York BEGIN:VTIMEZONE TZID:America/New_York X-LIC-LOCATION:America/New_York BEGIN:STANDARD DTSTART:20171105T020000 TZOFFSETFROM:-0400 TZOFFSETTO:-0500 RDATE:20181104T020000 TZNAME:EST END:STANDARD BEGIN:DAYLIGHT DTSTART:20180311T020000 TZOFFSETFROM:-0500 TZOFFSETTO:-0400 TZNAME:EDT END:DAYLIGHT END:VTIMEZONE BEGIN:VEVENT UID:1rortkmnnqldlfr3ep8prjv5i8@google.com DTSTAMP:20180503T080658Z CATEGORIES: CONTACT: DESCRIPTION:Title: Why does climate sensitivity go up as ocean heat uptake declines? A linear systems perspective.\n\nTransient climate sensitivity t ends to increase on multiple timescales in climate models subject to an ab rupt CO2 increase\, which suggests that:\n(1) we may be systematically und erestimating equilibrium sensitivity\nin the models\, and\n(2) constrainin g equilibrium sensitivity from observations is a\ntricky business at best. \nI will argue that the radiative feedback and ocean heat uptake processes governing transient sensitivity are intimately connected. Idealized GCM e xperiments show that the global climatic impact of spatially localized oce an heat uptake patterns are very sensitive to their geographical distribut ion. I will discuss these results in terms of the efficacy concept and a l inear systems perspective in which responses to individual climate forcing agents are additive. Heat uptake can be treated as a slowly varying forci ng on the atmosphere and surface\, whose efficacy is strongly determined b y its spatial pattern. An illustrative linear model demonstrates the emerg ence of increasing climate sensitivity as a simple consequence of the slow decay of high-efficacy sub-polar heat uptake. Shortwave cloud feedbacks a re a key player in this increasing climate sensitivity\, both in idealized and CMIP5-type models. I propose a causal physical mechanism linking sub- polar heat uptake to a global-scale increase in lower-tropospheric stabili ty. DTSTART;TZID=America/New_York:20170320T120000 DTEND;TZID=America/New_York:20170320T130000 SEQUENCE:0 SUMMARY:PAOC Colloquium: Brian Rose\, U Albany URL:http://oceans.mit.edu/event/paoc-colloquium-brian-rose-u-albany-2 X-ALT-DESC;FMTTYPE=text/html:\\n\\n\\n\\n\\nTitle: Why does climate sensitivity go up as ocean heat uptake declines? A linear systems perspective.\n\nTransient climate sensitivity tends to increase on multipl e timescales in climate models subject to an abrupt CO2 increase\, which s uggests that:\n(1) we may be systematically underestimating equilibrium se nsitivity\nin the models\, and\n(2) constraining equilibrium sensitivity f rom observations is a\ntricky business at best.\nI will argue that the rad iative feedback and ocean heat uptake processes governing transient sensit ivity are intimately connected. Idealized GCM experiments show that the gl obal climatic impact of spatially localized ocean heat uptake patterns are very sensitive to their geographical distribution. I will discuss these r esults in terms of the efficacy concept and a linear systems perspective i n which responses to individual climate forcing agents are additive. Heat uptake can be treated as a slowly varying forcing on the atmosphere and su rface\, whose efficacy is strongly determined by its spatial pattern. An i llustrative linear model demonstrates the emergence of increasing climate sensitivity as a simple consequence of the slow decay of high-efficacy sub -polar heat uptake. Shortwave cloud feedbacks are a key player in this inc reasing climate sensitivity\, both in idealized and CMIP5-type models. I p ropose a causal physical mechanism linking sub-polar heat uptake to a glob al-scale increase in lower-tropospheric stability. END:VEVENT END:VCALENDAR