date: Sun, 1 May 2005 21:23:55 +0200 from: Eystein Jansen subject: [Wg1-ar4-ch06] Fwd: Papers of potential interest to the AR4 to: wg1-ar4-ch06@joss.ucar.edu >Envelope-to: eystein.jansen@geo.uib.no >Date: Sun, 01 May 2005 01:10:03 -0500 >Subject: Papers of potential interest to the AR4 >From: Noah Diffenbaugh >To: , >CC: > >Dear Drs Overpeck and Jansen: > >I have attached pdfs of 4 papers that may be of interest to the Paleoclimate >chapter of the AR4. > >Thank you! >Noah > >-------------------- > >The papers are: > >Diffenbaugh, Noah S. and L.C. Sloan, Mid-Holocene orbital forcing of >regional-scale climate: a case study of western North America using a >high-resolution RCM, Journal of Climate, 17(15), 2927-2937, 2004. > >This study used a regional climate model to test the response of >regional-scale climate processes to mid-Holocene orbital forcing. We found >summer warming of 1 to 2.5 šC over most of the western United States, >suggesting that observed regional mid-Holocene temperature change can be >explained by direct orbital forcing alone, independent of climate system >feedbacks. In contrast, positive anomalies in mean annual P-E were in >disagreement with proxy reconstructions from the Pacific coast, suggesting >that direct orbital forcing of regional-scale atmospheric processes was not >the sole influence shaping the mid-Holocene moisture record of the Pacific >coast. > > >Diffenbaugh, Noah S., J.L. Bell and L.C. Sloan, Simulated changes in extreme >temperature and precipitation events at 6 ka, Palaeogeography, >Palaeoclimatology, Palaeoecology, preliminarily accepted to special issue, >December 2004. > >This study used a regional climate model to test the response of extreme >climate events to mid-Holocence orbital forcing, using the western North >America as a case study. We found that anomalies in annual extreme >precipitation event frequency were mostly positive throughout the region, as >were differences in extreme event contribution to total annual >precipitation. We also found large positive anomalies in extreme hot events, >with days in which the maximum daily temperature exceeded 32 šC 24 % more >frequent in the 6 ka integration and heat waves lasting up to 12 days >longer. We propose that such changes in the frequency and duration of >extreme climate events could have played a substantial role in shaping >paleoclimate records from a variety of regions. > > >Diffenbaugh, Noah S., L.C. Sloan and M.A. Snyder, Orbital suppression of >wind driven upwelling in the California Current at 6 ka, Paleoceanography, >18(2), 1051, 10.1019/2002PA000865, 2003. > >This study used a regional climate model to test the response of wind driven >upwelling in the California Current to Mid Holocene orbital forcing. The >seasonality of modern California Current wind driven coastal upwelling >simulated by the RCM is in strong agreement with observational data. >Further, we show that changes in the seasonality of solar insolation induced >by mid-Holocene Milankovitch forcing decrease early and peak season coastal >upwelling in the California Current, along with increasing late season >coastal upwelling. These results are in agreement with several marine and >terrestrial proxies, suggesting that, relative to present, California >Current activity during the mid-Holocene was characterized by a longer and >less vigorous upwelling season, with decreased seasonal contrast. > > >Diffenbaugh, Noah S. and L.C. Sloan, Global climate sensitivity to land >surface change: The Mid Holocene revisited, Geophysical Research Letters, >29(10), 1476, 10.1029/2002GL014880, 2002. > >This study tests the response of large-scale atmospheric processes to a >global mid-Holocene vegetation distribution reconstructed from the fossil >record. Large areas of the globe showed statistically significant >temperature sensitivity to these land surface changes, with the magnitude of >the vegetation forcing equal to the magnitude of 6 ka orbital forcing, >emphasizing the importance of accurate land surface distribution for both >model validation and future climate prediction. > >-- >Dr. Noah S. Diffenbaugh >Assistant Professor >Department of Earth and Atmospheric Sciences >550 Stadium Mall Drive >Purdue University >West Lafayette, IN, 47907-2051 > >(765) 494-0754 (office) >(765) 494-2434 (lab) >(765) 496-1210 (fax) > >diffenbaugh@purdue.edu >http://web.ics.purdue.edu/~ndiffenb > > > > > -- ______________________________________________________________ Eystein Jansen Professor/Director Bjerknes Centre for Climate Research and Dep. of Earth Science, Univ. of Bergen Allégaten 55 N-5007 Bergen NORWAY e-mail: eystein.jansen@geo.uib.no Phone: +47-55-583491 - Home: +47-55-910661 Fax: +47-55-584330 Attachment Converted: "c:\eudora\attach\Diffenbaugh_PA_03.pdf" Attachment Converted: "c:\eudora\attach\Diffenbaugh_JoC_04.pdf" Attachment Converted: "c:\eudora\attach\Diffenbaugh_GRL_02.pdf" Attachment Converted: "c:\eudora\attach\nsd_p3_ms.pdf" _______________________________________________ Wg1-ar4-ch06 mailing list Wg1-ar4-ch06@joss.ucar.edu http://www.joss.ucar.edu/mailman/listinfo/wg1-ar4-ch06