Alaska Holocene Midge Data and July Temperature Reconstructions Clegg, B.F.; Kelly, R.F.; Clarke, G.H.; Walker, I.R.; Hu, F.S. Clegg, B.F. Kelly, R.F. Clarke, G.H. Walker, I.R. Hu, F.S. Air Temperature Reconstruction Arctic Oscillation (AO) Milankovitch earth science/paleoclimate/climate reconstructions|insect|paleolimnology (age at sample end,null,null,calendar year before present,null,climate reconstructions|insect|paleolimnology,null,null,N,null) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Cryptochironomus sp.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Glyptotendipes sp.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Phaenopsectra flavipes type) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Procladius sp.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Zalutschia type A) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Limnophyes sp.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Psectrocladius septentrionalis) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Stempellinella/Zavrelia indet.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Tanytarsina indet.) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (surface air temperature,midge assemblage,null,degree Celsius,Jul,climate reconstructions|insect|paleolimnology,null,regression analysis,N,WA-PLS2) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Chironomus sp.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Corynocera ambigua) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Endochironomus sp.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Parametriocnemus/Paraphaenocladius indet.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Paratendipes sp.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Pentaneurini indet.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Cladopelma sp.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Corynoneura/Thienemanniella indet.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Eukiefferiella/Tvetenia indet.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Labrundinia sp.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Parachironomus sp.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Parakiefferiella triquetra) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Polypedilum sp.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Psectrocladius sordidellus type) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Smittia/Pseudosmittia indet.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Chaoboridae indet.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Cricotopus/Orthocladius indet.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Derotanypus sp.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Einfeldia sp.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Lauterborniella/Zavreliella indet.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Metriocnemus sp.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Microtendipes sp.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Monodiamesa sp.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Parakiefferiella sp. B) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Pseudochironomus sp.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Stempellina sp.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Paraclaius sp.) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (depth at sample end,null,null,centimeter,null,climate reconstructions|insect|paleolimnology,null,null,N,null) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Lasiodiamesa sp.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Orthocladinae sp. 2) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Stictochironomus sp.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Ceratopogonidae indet.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Chaeoborus sp.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Corynocera oliveri) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Dicrotendipes sp.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Heterotrissocladius sp.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Micropsectra sp.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Sergentia coracina type) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Allo-/Mesopsectrocladius indet.) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (surface air temperature,midge assemblage,one standard error,degree Celsius,Jul,climate reconstructions|insect|paleolimnology,null,regression analysis,N,WA-PLS2; sample-specific standard error of prediction) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (depth at sample start,null,null,centimeter,null,climate reconstructions|insect|paleolimnology,null,null,N,null) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Cladotanytarsus mancus type) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Cryptotendipes sp.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Doithrix/Pseudorthocladius indet.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,indeterminate headcapsule) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Monopsectrocladius sp.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Nanocladius sp.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Pagastiella sp.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Parakiefferiella nigra) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,count,null,insect|paleolimnology,raw,null,N,Synorthocladius sp.) earth science/paleoclimate/insecta (Hudson Lake Alaska>LATITUDE 61.9>LONGITUDE -145.6833) (Screaming Lynx Lake>LATITUDE 66.0667>LONGITUDE -145.4) (Rainbow Lake Alaska>LATITUDE 60.7167>LONGITUDE -150.8) Regional climate responses to large-scale forcings, such as precessional changes in solar irradiation and increases in anthropogenic greenhouse gases, may be nonlinear as a result of complex interactions among earth system components. Such nonlinear behaviors constitute a major source of climate "surprises" with important socioeconomic and ecological implications. Paleorecords are key for elucidating patterns and mechanisms of nonlinear responses to radiative forcing, but their utility has been greatly limited by the paucity of quantitative temperature reconstructions. Here we present Holocene July temperature reconstructions on the basis of midge analysis of sediment cores from three Alaskan lakes. Results show that summer temperatures during 10,000-5,500 calibrated years (cal) B.P. were generally lower than modern and that peak summer temperatures around 5,000 were followed by a decreasing trend toward the present. These patterns stand in stark contrast with the trend of precessional insolation, which decreased by ~10% from 10,000 y ago to the present. Cool summers before 5,500 cal B.P. coincided with extensive summer ice cover in the western Arctic Ocean, persistence of a positive phase of the Arctic Oscillation, predominantly La Niña-like conditions, and variation in the position of the Alaskan treeline. These results illustrate nonlinear responses of summer temperatures to Holocene insolation radiative forcing in the Alaskan sub-Arctic, possibly because of state changes in the Arctic Oscillation and El Niño-Southern Oscillation and associated land-atmosphere-ocean feedbacks. STUDY NOTES: Holocene midge data and midge-inferred july temperatures from 3 lakes in Alaska, USA. Chironomid data are expressed as raw headcapsule counts. Taxonomy follows Barley et al. (2006). NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Clegg, B.F. Investigator : Kelly, R.F. Investigator : Clarke, G.H. Investigator : Walker, I.R. Investigator : Hu, F.S. 2012-02-04 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/12443 https://www1.ncdc.noaa.gov/pub/data/paleo/insecta/chironomidae/northamerica/usa/alaska/alaska2011midge-t.txt https://www1.ncdc.noaa.gov/pub/data/paleo/insecta/chironomidae/northamerica/usa/alaska/alaska2011midge-t.xls https://www1.ncdc.noaa.gov/pub/data/paleo/insecta/chironomidae/northamerica/usa/alaska/alaska2011midge-t.txt https://www1.ncdc.noaa.gov/pub/data/paleo/insecta/chironomidae/northamerica/usa/alaska/alaska2011midge-t.xls English https://www.ncdc.noaa.gov/paleo/study/12443 https://www1.ncdc.noaa.gov/pub/data/paleo/insecta/chironomidae/northamerica/usa/alaska/alaska2011midge-t.txt https://www1.ncdc.noaa.gov/pub/data/paleo/insecta/chironomidae/northamerica/usa/alaska/alaska2011midge-t.xls Clegg, B.F., R. Kelly, G.H. Clarke, I.R. Walker, and F.S. Hu. 2011. Nonlinear response of summer temperature to Holocene insolation forcing in Alaska. Proceedings of the National Academy of Sciences (PNAS), Vol. 108, No. 48, pp. 19299-19304, 29 November 2011. doi:10.1073/pnas.1110913108 START YEAR: 13506 cal yr BP * END YEAR: -54 cal yr BP -150.8 60.7167 -145.4 66.0667