Global-warming Global-warming reverse-impact reverse-impact : : observed summer-daytime coastal- observed summer-daytime coastal- cooling cooling in coastal California air-basins in coastal California air-basins R. Bornstein R. Bornstein , San Jose State , San Jose State University University [email protected][email protected]B. Lebassi, J. E. González, D. B. Lebassi, J. E. González, D. Fabris, Fabris, E. Maurer, Santa Clara University E. Maurer, Santa Clara University N. Miller, Berkeley National N. Miller, Berkeley National Laboratory Laboratory Presented at ASU Presented at ASU
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R. Bornstein , San Jose State University pblmodel@hotmail
Global-warming reverse-impact : observed summer-daytime coastal-cooling in coastal California air-basins. R. Bornstein , San Jose State University [email protected] B. Lebassi, J. E. González, D. Fabris, E. Maurer, Santa Clara University N. Miller, Berkeley National Laboratory - PowerPoint PPT Presentation
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• CoastalCoastal SSTsSSTs – ICOADS dataICOADS data– 2-deg horiz resolution2-deg horiz resolution– Warming, butWarming, but– At slower rate than at At slower rate than at
ANALYSESANALYSES• 1970-2005 data used1970-2005 data used• Annual & summer Annual & summer
warming/ cooling trends warming/ cooling trends (K/decade) for SST, T(K/decade) for SST, Tmaxmax, , TTminmin
• Spatial dist of summer Spatial dist of summer
TTmax-trends plotted -trends plotted (in 2 black boxes) (in 2 black boxes) – South Coast Air Basin South Coast Air Basin – SFBA and Central Valley SFBA and Central Valley
• Summer land-sea TSummer land-sea Taver--grad (surrogate for p-grad (surrogate for p-grad) trend calculated by grad) trend calculated by use of use of – SST: SFBA black-boxSST: SFBA black-box– 2-m land-values:2-m land-values: red-box red-box
Changes in Diurnal temperature-range (DTR) values at Changes in Diurnal temperature-range (DTR) values at all Calif all Calif • daytime-warming (mainly inland) sites:daytime-warming (mainly inland) sites: 0.05 0.05 K/decade K/decade
(as T(as Tmax increased a bit faster than did Tincreased a bit faster than did Tmin))• daytime-cooling (mainly coastal) sites:daytime-cooling (mainly coastal) sites: -0.61 -0.61 K/decadeK/decade
(as T(as Tmax decreased and Tcreased and Tmin increased) increased)
Significant South Coast Significant South Coast Air Basin TopographyAir Basin Topography
SCAB 1970-2005 summerSCAB 1970-2005 summer T Tmax max warming/cooling trends (K/decade) warming/cooling trends (K/decade)
Significant SFBA and CenValleySignificant SFBA and CenValleyTopographyTopography
SUMMARY SUMMARY • MIN-TEMPSMIN-TEMPS IN CALIF WARMED FASTER IN CALIF WARMED FASTER
THAN THAN MAX-TEMPS MAX-TEMPS ASYMMETRIC ASYMMETRIC WARMINGWARMING
• SUMMER DAYTIME MAX-TEMPSSUMMER DAYTIME MAX-TEMPS COOLEDCOOLED IN IN LOW-ELEVATION LOW-ELEVATION COASTALCOASTAL AIR- BASINS AIR- BASINS
• FOLLOWING AREAS FOLLOWING AREAS COOLED IN CENTRAL COOLED IN CENTRAL CALIFORNIA:CALIFORNIA:– MARINE LOWLANDSMARINE LOWLANDS– MONTEREYMONTEREY– SANTA CLARA VALLEYSANTA CLARA VALLEY– LIVERMORE VALLEYLIVERMORE VALLEY– WESTERN HALF OF SACRAMENTO VALLEYWESTERN HALF OF SACRAMENTO VALLEY
GOOD IMPLICATIONSGOOD IMPLICATIONS
• AGRICULTURAL AREAS AGRICULTURAL AREAS MAY MAY NOT SHRINKNOT SHRINKe.g.: e.g.: NAPA WINE NAPA WINE AREAS MAY AREAS MAY NOT GO EXTINCTNOT GO EXTINCT
• ENERGY-ENERGY-NEED FOR COOLING NEED FOR COOLING MAY NOT INCREASE AS MAY NOT INCREASE AS RAPIDLY AS POPULATIONRAPIDLY AS POPULATION
• LOWER HUMAN LOWER HUMAN HEAT-HEAT-STRESSSTRESS & MORTALITY RATES & MORTALITY RATES
• URBAN-OZONEURBAN-OZONE LEVELS WILL LEVELS WILL CONTINUE TO FALLCONTINUE TO FALL
IMPLICATIONS FOR CALIF IMPLICATIONS FOR CALIF OZONE OZONE
• PAST DECREASES MAY BE IN-PART DUE TO PAST DECREASES MAY BE IN-PART DUE TO JJA MAX-TEMP COOLING-TRENDS & NOT JJA MAX-TEMP COOLING-TRENDS & NOT ONLY TO EMISSION REDUCTIONSONLY TO EMISSION REDUCTIONS
• WHEN MAX-T DECREASES, THE FOLLOWING WHEN MAX-T DECREASES, THE FOLLOWING ALSO DECREASEALSO DECREASE::– BIOGENIC PRECURSOR EMISSIONSBIOGENIC PRECURSOR EMISSIONS