Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder

Thomas N. Chase

Research Interests

Much of my recent work has addressed the climatic effects of landcover change both through climate model studies and observational analysis. I am particularly interested in atmospheric circulation changes which may have resulted from recent landcover changes and interactions with other natural circulation regimes such as those due to El Nino/Southern Oscillation or monsoons. Because changes in tropical circulation have been strongly related to the recently observed planetary surface warming, this research is relevant to the issues of greenhouse warming. A main issue for the future is adequately characterizing the changes in land surface properties over the course of time.

I have also been involved in examining general feedback behavior to changes in the climate system, particularly as mediated by the hydrological cycle. Because the hydrological cycle is strongly coupled to the biosphere, landcover change has many implications for hydrological cycle feedbacks and may explain some discrepancies between model simulations and observed behavior. One example of a regulation mechanism mediated by the hydrological cycle under investigation here is seen in observations of mid-tropospheric Arctic winter temperatures where a minimum is reached in late autumn which is not exceeded later in the winter despite several months of continued net energy loss. This minimum temperature can be related to convective activity over open ocean and suggest the presence of an active regulation mechanism.

Current Research

Variability in temperature extremes and atmospheric moisture

We found that there is an increasing trend in heat waves and positive specific-humidity anomalies and a decreasing trend in cold waves and negative specific-humidity anomalies. And similar patterns in the global trend in variability exist for both temperature and specific humidity. This means areas of increased variability are not necessarily the areas that have experienced extreme heat waves. The follow-up study to this work relates heat waves globally to changes in soil moisture.One theoretical consequence of the CO2-warming hypothesis is that increases in atmospheric humidity will greatly amplify the warming signal due to CO2 alone and will also amplify extremes. We investigated the magnitude and spatial extent of extreme temperature and specific humidity events in the extra- tropical northern hemisphere.

Chase is also one of the CIRES Faculty who teach at the University of Colorado Boulder with teaching loads equivalent to those of CU faculty rostered solely in departments and programs.

A figure from a new analysis of Northern Hemisphere summer temperatures and specific humidity anomalies, co-authored by Chase. These figures show National Centers for Environmental Prediction Reanalysis temperature and specific humidity anomaly distributions for the three largest, most extreme heat waves in the NCEP record: (a–b) 2003, (c–d) 2010, (e–f) 2012. Contours encircle areas exceeding 2.5, 3.0, and 3.5 standard deviations. Figure credit: Gill et al. Journal of Geophysical

View Publications

  • Halder, S, SK Saha, PA Dirmeyer, TN Chase and BN Goswami (2016), Investigating the impact of land-use land-cover change on Indian summer monsoon daily rainfall and temperature during 1951-2005 using a regional climate model. Hydrol. Earth Syst. Sci. Version: 1 20 (5) 1765-1784, issn: 1027-5606, ids: DO5ZX, doi: 10.5194/hess-20-1765-2016
  • Wolter, K, M Hoerling, JK Eischeid, GJ van Oldenborgh, XW Quan, JE Walsh, TN Chase and RM Dole (2015), HOW UNUSUAL WAS THE COLD WINTER OF 2013/14 IN THE UPPER MIDWEST?. Bull. Amer. Meteorol. Soc. Version: 1 96 (12) S10-S14, issn: 0003-0007, ids: DB4SL, doi: 10.1175/BAMS-D-15-00126.1
  • Gill, EC, TN Chase, RA Sr and K Wolter (2013), Northern Hemisphere summer temperature and specific humidity anomalies from two reanalyses. J. Geophys. Res.-Atmos. Version: 1 118 (15) 8297-8305, issn: 2169-897X, ids: 213DA, doi: 10.1002/jgrd.50635
  • Bailey, A, TN Chase, JJ Cassano and D Noone (2011), Changing Temperature Inversion Characteristics in the US Southwest and Relationships to Large-Scale Atmospheric Circulation. J. Appl. Meteorol. Climatol. Version: 1 50 (6) 1307-1323, issn: 1558-8424, ids: 786HS, doi: 10.1175/2011JAMC2584.1
  • Lee, E, WJ Sacks, TN Chase and JA Foley (2011), Simulated impacts of irrigation on the atmospheric circulation over Asia. J. Geophys. Res.-Atmos. Version: 1 116 , Art. No. D08114, issn: 2169-897X, ids: 754KI, doi: 10.1029/2010JD014740
  • Anantharaj, VG, US Nair, P Lawrence, TN Chase, S Christopher and T Jones (2010), Comparison of satellite-derived TOA shortwave clear-sky fluxes to estimates from GCM simulations constrained by satellite observations of land surface characteristics. Int. J. Climatol. Version: 1 30 (13) 2088-2104, issn: 0899-8418, ids: 680CZ, doi: 10.1002/joc.2107
  • Lawrence, PJ and TN Chase (2010), Investigating the climate impacts of global land cover change in the community climate system model. Int. J. Climatol. Version: 1 30 (13) 2066-2087, issn: 0899-8418, ids: 680CZ, doi: 10.1002/joc.2061
  • Mahmood, R, RA Pielke, KG Hubbard, D Niyogi, G Bonan, P Lawrence, R McNider, C McAlpine, A Etter, S Gameda, BD Qian, A Carleton, A Beltran-Przekurat, T Chase, AI Quintanar, JO Adegoke, S Vezhapparambu, G Conner, S Asefi, E Sertel, DR Legates, YL Wu, R Hale, OW Frauenfeld, A Watts, M Shepherd, C Mitra, VG Anantharaj, S Fall, R Lund, A Trevino, P Blanken, JY Du, HI Chang, RE Leeper, US Nair, S Dobler, R Deo and J Syktus (2010), IMPACTS OF LAND USE/LAND COVER CHANGE ON CLIMATE AND FUTURE RESEARCH PRIORITIES. Bull. Amer. Meteorol. Soc. Version: 1 91 (1) 37-46, issn: 0003-0007, ids: 567CO, doi: 10.1175/2009BAMS2769.1
  • Lawrence, PJ and TN Chase (2009), Climate Impacts of Making Evapotranspiration in the Community Land Model (CLM3) Consistent with the Simple Biosphere Model (SiB). J. Hydrometeorol. Version: 1 10 (2) 374-394, issn: 1525-755X, ids: 439PQ, doi: 10.1175/2008JHM987.1
  • Lee, E, TN Chase, B Rajagopalan, RG Barry, TW Biggs and PJ Lawrence (2009), Effects of irrigation and vegetation activity on early Indian summer monsoon variability. Int. J. Climatol. Version: 1 29 (4) 573-581, issn: 0899-8418, ids: 419LL, doi: 10.1002/joc.1721
  • Biggs, TW, CA Scott, A Gaur, JP Venot, T Chase and E Lee (2008), Impacts of irrigation and anthropogenic aerosols on the water balance, heat fluxes, and surface temperature in a river basin. Water Resour. Res. Version: 1 44 (12) , Art. No. W12415, issn: 0043-1397, ids: 383RM, doi: 10.1029/2008WR006847
  • Herman, B, M Barlage, TN Chase and RA Pielke (2008), Update on a proposed mechanism for the regulation of minimum midtropospheric and surface temperatures in the Arctic and Antarctic. J. Geophys. Res.-Atmos. Version: 1 113 , Art. No. D24101, issn: 2169-897X, ids: 386KY, doi: 10.1029/2008JD009799
  • Lee, E, TN Chase, PJ Lawrence and B Rajagopalan (2008), Model assessment of the observed relationship between El Nino and the northern East Asian summer monsoon using the Community Climate System Model Community Atmosphere Model-Community Land Model version 3 (CAM-CLM3). J. Geophys. Res.-Atmos. Version: 1 113 (D20) , Art. No. D20118, issn: 2169-897X, ids: 368CD, doi: 10.1029/2008JD009926
  • Lee, E, TN Chase and B Rajagopalan (2008), Highly improved predictive skill in the forecasting of the East Asian summer monsoon. Water Resour. Res. Version: 1 44 (10) , Art. No. W10422, issn: 0043-1397, ids: 368ET, doi: 10.1029/2007WR006514
  • Leavitt, SW, TN Chase, B Rajagopalan, E Lee and PJ Lawrence (2008), Southwestern US tree-ring carbon isotope indices as a possible proxy for reconstruction of greenness of vegetation. Geophys. Res. Lett. Version: 1 35 (12) , Art. No. L12704, issn: 0094-8276, ids: 317XC, doi: 10.1029/2008GL033894
  • Lee, E, TN Chase and B Rajagopalan (2008), Seasonal forecasting of East Asian summer monsoon based on oceanic heat sources. Int. J. Climatol. Version: 1 28 (5) 667-678, issn: 0899-8418, ids: 294UG, doi: 10.1002/joc.1551
  • Pielke, RA, JO Adegoke, TN Chase, CH Marshall, T Matsui and D Niyogi (2007), A new paradigm for assessing the role of agriculture in the climate system and in climate change. Agric. For. Meteorol. Version: 1 International Workshop on Contribution of Agriculture to the State of Climate 142 (4-Feb) 234-254, Ottawa, CANADA, SEP 27-30, 2004, issn: 0168-1923, ids: 138SG, doi: 10.1016/j.agrformet.2006.06.012
  • Lawrence, PJ and TN Chase (2007), Representing a new MODIS consistent land surface in the Community Land Model (CLM 3.0). J. Geophys. Res.-Biogeosci. Version: 1 112 (G1) , Art. No. G01023, issn: 0148-0227, ids: 147QT, doi: 10.1029/2006JG000168
  • Chase, TN, K Wolter, RA Pielke and I Rasool (2006), Was the 2003 European summer heat wave unusual in a global context?. Geophys. Res. Lett. Version: 1 33 (23) , Art. No. L23709, issn: 0094-8276, ids: 118KX, doi: 10.1029/2006GL027470
  • Nordstrom, KM, VK Gupta and TN Chase (2005), Role of the hydrological cycle in regulating the planetary climate system of a simple nonlinear dynamical model. Nonlinear Process Geophys. Version: 1 12 (5) 741-753, issn: 1023-5809, ids: 961EA
  • Chase, TN, RA Pielke, B Herman and X Zeng (2004), Likelihood of rapidly increasing surface temperatures unaccompanied by strong warming in the free troposphere. Clim. Res. Version: 1 25 (3) 185-190, issn: 0936-577X, ids: 802WY, doi: 10.3354/cr025185
  • Tsukernik, M, TN Chase, MC Serreze, RG Barry, R Pielke, B Herman and X Zeng (2004), On the regulation of minimum mid-tropospheric temperatures in the Arctic. Geophys. Res. Lett. Version: 1 31 (6) , Art. No. L06112, issn: 0094-8276, ids: 806MG, doi: 10.1029/2003GL018831
  • Pielke, RA, R Klein, G Maricle and T Chase (2003), Hydrogen cars and water vapor. Science Version: 1 302 (5649) 1329-1329, issn: 0036-8075, ids: 745HP, PubMed ID: 14631019
  • Chase, TN, JA Knaff, RA Pielke and E Kalnay (2003), Changes in global monsoon circulations since 1950. Nat. Hazards Version: 1 29 (2) 229-254, issn: 0921-030X, ids: 673XX, doi: 10.1023/A:1023638030885
  • Herman, BM, XB Zeng, T Chase and R Pielke (2002), More heat over greenhouse gases. Phys. Today Version: 1 55 (5) 14-14, issn: 0031-9228, ids: 547KT, doi: 10.1063/1.1485563
  • Pielke, RA, G Marland, RA Betts, TN Chase, JL Eastman, JO Niles, DDS Niyogi and SW Running (2002), The influence of land-use change and landscape dynamics on the climate system: relevance to climate-change policy beyond the radiative effect of greenhouse gases. Philos. Trans. R. Soc. Lond. Ser. A-Math. Phys. Eng. Sci. Version: 1 360 (1797) 1705-1719, issn: 1364-503X, ids: 582GB, doi: 10.1098/rsta.2002.1027
  • Gregory, PJ, JSI Ingram, R Andersson, RA Betts, V Brovkin, TN Chase, PR Grace, AJ Gray, N Hamilton, TB Hardy, SM Howden, A Jenkins, M Meybeck, M Olsson, I Ortiz-Monasterio, CA Palm, TW Payn, M Rummukainen, RE Schulze, M Thiem, C Valentin and MJ Wilkinson (2002), Environmental consequences of alternative practices for intensifying crop production. Agric. Ecosyst. Environ. Version: 1 88 (3) 279-290, issn: 0167-8809, ids: 531JN, doi: 10.1016/S0167-8809(01)00263-8
  • Chase, TN, B Herman, RA Pielke, X Zeng and M Leuthold (2002), A proposed mechanism for the regulation of minimum midtropospheric temperatures in the Arctic. J. Geophys. Res.-Atmos. Version: 1 107 (D14) , Art. No. 4193, issn: 0747-7309, ids: 610TQ, doi: 10.1029/2001JD001425
  • Otterman, J, R Atlas, SH Chou, JC Jusem, RA Pielke, TN Chase, J Rogers, GL Russell, SD Schubert, YC Sud and J Terry (2002), Are stronger North-Atlantic southwesterlies the forcing to the late-winter warming in Europe?. Int. J. Clim. Version: 1 22 (6) 743-750, issn: 0899-8418, ids: 562BK, doi: 10.1002/joc.681
  • Pielke, RA, TN Chase, TGF Kittel, JA Knaff and J Eastman (2001), Analysis of 200 mbar zonal wind for the period 1958-1997. J. Geophys. Res.-Atmos. Version: 1 106 (D21) 27287-27290, issn: 2169-897X, ids: 494XZ, doi: 10.1029/2000JD000299
  • Chase, TN, RA Pielke, TGF Kittel, M Zhao, AJ Pitman, SW Running and RR Nemani (2001), Relative climatic effects of landcover change and elevated carbon dioxide combined with aerosols: A comparison of model results and observations. J. Geophys. Res.-Atmos. Version: 1 106 (D23) 31685-31691, issn: 2169-897X, ids: 515DA, doi: 10.1029/2000JD000129
  • Zhao, M, AJ Pitman and TN Chase (2001), Climatic effects of land cover change at different carbon dioxide levels. Clim. Res. Version: 1 17 (1) 1-18, issn: 0936-577X, ids: 478CB, doi: 10.3354/cr017001
  • Zhao, M, AJ Pitman and T Chase (2001), The impact of land cover change on the atmospheric circulation. Clim. Dyn. Version: 1 17 (6-May) 467-477, issn: 0930-7575, ids: 411YM
  • Chase, TN, RA Pielke, JA Knaff, TGF Kittel and JL Eastman (2000), A comparison of regional trends in 1979-1997 depth-averaged tropospheric temperatures. Int. J. Climatol. Version: 1 20 (5) 503-518, issn: 0899-8418, ids: 313GN, doi: 10.1002/(SICI)1097-0088(200004)20:5<503::AID-JOC491>3.0.CO;2-0
  • Chase, TN, RA Pielke, TGF Kittel, RR Nemani and SW Running (2000), Simulated impacts of historical land cover changes on global climate in northern winter. Clim. Dyn. Version: 1 16 (3-Feb) 93-105, issn: 0930-7575, ids: 285DP, doi: 10.1007/s003820050007
  • Pielke, RA, RL Walko, LT Steyaert, PL Vidale, GE Liston, WA Lyons and TN Chase (1999), The influence of anthropogenic landscape changes on weather in south Florida. Mon. Weather Rev. Version: 1 127 (7) 1663-1673, issn: 0027-0644, ids: 221VZ, doi: 10.1175/1520-0493(1999)127<1663:TIOALC>2.0.CO;2
  • Chase, TN, RA Pielke, TGF Kittel, JS Baron and TJ Stohlgren (1999), Potential impacts on Colorado Rocky Mountain weather due to land use changes on the adjacent Great Plains. J. Geophys. Res.-Atmos. Version: 1 104 (D14) 16673-16690, issn: 0747-7309, ids: 220ET, doi: 10.1029/1999JD900118
  • Pielke, RA, J Eastman, TN Chase, J Knaff and TGF Kittel (1998), 1973-1996 trends in depth-averaged tropospheric temperature. J. Geophys. Res.-Atmos. Version: 1 103 (D14) 16927-16933, issn: 2169-897X, ids: 104BK, doi: 10.1029/98JD01645
  • Stohlgren, TJ, TN Chase, RA Pielke, TGF Kittel and JS Baron (1998), Evidence that local land use practices influence regional climate, vegetation, and stream flow patterns in adjacent natural areas. Glob. Change Biol. Version: 1 4 (5) 495-504, issn: 1354-1013, ids: 106ZQ, doi: 10.1046/j.1365-2486.1998.t01-1-00182.x
  • Chase, TN, RA Pielke, TGF Kittel, R Nemani and SW Running (1996), Sensitivity of a general circulation model to global changes in leaf area index. J. Geophys. Res.-Atmos. Version: 1 101 (D3) 7393-7408, issn: 0148-0227, ids: UB986, doi: 10.1029/95JD02417
  • Nemani, RR, SW Running, RA Pielke and TN CHase (1996), Global vegetation cover changes from coarse resolution satellite data. J. Geophys. Res.-Atmos. Version: 1 101 (D3) 7157-7162, issn: 0148-0227, ids: UB986, doi: 10.1029/95JD02138