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. HYDROLOGY AND EARTH SYSTEM SCIENCES, 20(5), 1765-1784. 10.5194/hess-20-1765-2016
  • Wolter, K, M Hoerling, JK Eischeid, GJ van Oldenborgh, XW Quan, JE Walsh, TN Chase and RM Dole. (DEC 2015). HOW UNUSUAL WAS THE COLD WINTER OF 2013/14 IN THE UPPER MIDWEST?. BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY, 96(12), S10-S14. 10.1175/BAMS-D-15-00126.1
  • Gill, EC, TN Chase, RA Sr and K Wolter. (16-Aug 2013). Northern Hemisphere summer temperature and specific humidity anomalies from two reanalyses. JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 118(15), 8297-8305. 10.1002/jgrd.50635
  • Bailey, A, TN Chase, JJ Cassano and D Noone. (JUN 2011). Changing Temperature Inversion Characteristics in the US Southwest and Relationships to Large-Scale Atmospheric Circulation. JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY, 50(6), 1307-1323. 10.1175/2011JAMC2584.1
  • Lee, E, WJ Sacks, TN Chase and JA Foley. (21-Apr 2011). Simulated impacts of irrigation on the atmospheric circulation over Asia. JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 116. 10.1029/2010JD014740
  • Anantharaj, VG, US Nair, P Lawrence, TN Chase, S Christopher and T Jones. (NOV 2010). Comparison of satellite-derived TOA shortwave clear-sky fluxes to estimates from GCM simulations constrained by satellite observations of land surface characteristics. INTERNATIONAL JOURNAL OF CLIMATOLOGY, 30(13), 2088-2104. 10.1002/joc.2107
  • Lawrence, PJ and TN Chase. (NOV 2010). Investigating the climate impacts of global land cover change in the community climate system model. INTERNATIONAL JOURNAL OF CLIMATOLOGY, 30(13), 2066-2087. 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. (JAN 2010). IMPACTS OF LAND USE/LAND COVER CHANGE ON CLIMATE AND FUTURE RESEARCH PRIORITIES. BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY, 91(1), 37-46. 10.1175/2009BAMS2769.1
  • Lawrence, PJ and TN Chase. (APR 2009). Climate Impacts of Making Evapotranspiration in the Community Land Model (CLM3) Consistent with the Simple Biosphere Model (SiB). JOURNAL OF HYDROMETEOROLOGY, 10(2), 374-394. 10.1175/2008JHM987.1
  • Lee, E, TN Chase, B Rajagopalan, RG Barry, TW Biggs and PJ Lawrence. (30-Mar 2009). Effects of irrigation and vegetation activity on early Indian summer monsoon variability. INTERNATIONAL JOURNAL OF CLIMATOLOGY, 29(4), 573-581. 10.1002/joc.1721
  • Biggs, TW, CA Scott, A Gaur, JP Venot, T Chase and E Lee. (11-Dec 2008). Impacts of irrigation and anthropogenic aerosols on the water balance, heat fluxes, and surface temperature in a river basin. WATER RESOURCES RESEARCH, 44(12). 10.1029/2008WR006847
  • Herman, B, M Barlage, TN Chase and RA Pielke. (16-Dec 2008). Update on a proposed mechanism for the regulation of minimum midtropospheric and surface temperatures in the Arctic and Antarctic. JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 113. 10.1029/2008JD009799
  • Lee, E, TN Chase, PJ Lawrence and B Rajagopalan. (30-Oct 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). JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 113(D20). 10.1029/2008JD009926
  • Lee, E, TN Chase and B Rajagopalan. (29-Oct 2008). Highly improved predictive skill in the forecasting of the East Asian summer monsoon. WATER RESOURCES RESEARCH, 44(10). 10.1029/2007WR006514
  • Leavitt, SW, TN Chase, B Rajagopalan, E Lee and PJ Lawrence. (21-Jun 2008). Southwestern US tree-ring carbon isotope indices as a possible proxy for reconstruction of greenness of vegetation. GEOPHYSICAL RESEARCH LETTERS, 35(12). 10.1029/2008GL033894
  • Lee, E, TN Chase and B Rajagopalan. (30-Apr 2008). Seasonal forecasting of East Asian summer monsoon based on oceanic heat sources. INTERNATIONAL JOURNAL OF CLIMATOLOGY, 28(5), 667-678. 10.1002/joc.1551
  • Pielke, RA, JO Adegoke, TN Chase, CH Marshall, T Matsui and D Niyogi. (12-Feb 2007). A new paradigm for assessing the role of agriculture in the climate system and in climate change. AGRICULTURAL AND FOREST METEOROLOGY, 142(4-Feb), 234-254. 10.1016/j.agrformet.2006.06.012
  • Lawrence, PJ and TN Chase. (17-Mar 2007). Representing a new MODIS consistent land surface in the Community Land Model (CLM 3.0). JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES, 112(G1). 10.1029/2006JG000168
  • Chase, TN, K Wolter, RA Pielke and I Rasool. (14-Dec 2006). Was the 2003 European summer heat wave unusual in a global context?. GEOPHYSICAL RESEARCH LETTERS, 33(23). 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 PROCESSES IN GEOPHYSICS, 12(5), 741-753.
  • Chase, TN, RA Pielke, B Herman and X Zeng. (23-Jan 2004). Likelihood of rapidly increasing surface temperatures unaccompanied by strong warming in the free troposphere. CLIMATE RESEARCH, 25(3), 185-190. 10.3354/cr025185
  • Tsukernik, M, TN Chase, MC Serreze, RG Barry, R Pielke, B Herman and X Zeng. (20-Mar 2004). On the regulation of minimum mid-tropospheric temperatures in the Arctic. GEOPHYSICAL RESEARCH LETTERS, 31(6). 10.1029/2003GL018831
  • Pielke, RA, R Klein, G Maricle and T Chase. (21-Nov 2003). Hydrogen cars and water vapor. SCIENCE, 302(5649), 1329-1329.
  • Chase, TN, JA Knaff, RA Pielke and E Kalnay. (JUN 2003). Changes in global monsoon circulations since 1950. NATURAL HAZARDS, 29(2), 229-254. 10.1023/A:1023638030885
  • Herman, BM, XB Zeng, T Chase and R Pielke. (MAY 2002). More heat over greenhouse gases. PHYSICS TODAY, 55(5), 14-14. 10.1063/1.1485563
  • Pielke, RA, G Marland, RA Betts, TN Chase, JL Eastman, JO Niles, DDS Niyogi and SW Running. (15-Aug 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. PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON SERIES A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, 360(1797), 1705-1719. 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. (MAR 2002). Environmental consequences of alternative practices for intensifying crop production. AGRICULTURE ECOSYSTEMS & ENVIRONMENT, 88(3), 279-290. 10.1016/S0167-8809(01)00263-8
  • Chase, TN, B Herman, RA Pielke, X Zeng and M Leuthold. (JUL 2002). A proposed mechanism for the regulation of minimum midtropospheric temperatures in the Arctic. JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 107(D14). 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. (MAY 2002). Are stronger North-Atlantic southwesterlies the forcing to the late-winter warming in Europe?. INTERNATIONAL JOURNAL OF CLIMATOLOGY, 22(6), 743-750. 10.1002/joc.681
  • Pielke, RA, TN Chase, TGF Kittel, JA Knaff and J Eastman. (16-Nov 2001). Analysis of 200 mbar zonal wind for the period 1958-1997. JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 106(D21), 27287-27290. 10.1029/2000JD000299
  • Chase, TN, RA Pielke, TGF Kittel, M Zhao, AJ Pitman, SW Running and RR Nemani. (16-Dec 2001). Relative climatic effects of landcover change and elevated carbon dioxide combined with aerosols: A comparison of model results and observations. JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 106(D23), 31685-31691. 10.1029/2000JD000129
  • Zhao, M, AJ Pitman and TN Chase. (4-Jul 2001). Climatic effects of land cover change at different carbon dioxide levels. CLIMATE RESEARCH, 17(1), 1-18. 10.3354/cr017001
  • Zhao, M, AJ Pitman and T Chase. (2001). The impact of land cover change on the atmospheric circulation. CLIMATE DYNAMICS, 17(6-May), 467-477.
  • Chase, TN, RA Pielke, JA Knaff, TGF Kittel and JL Eastman. (APR 2000). A comparison of regional trends in 1979-1997 depth-averaged tropospheric temperatures. INTERNATIONAL JOURNAL OF CLIMATOLOGY, 20(5), 503-518. 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. (FEB 2000). Simulated impacts of historical land cover changes on global climate in northern winter. CLIMATE DYNAMICS, 16(3-Feb), 93-105. 10.1007/s003820050007
  • Pielke, RA, RL Walko, LT Steyaert, PL Vidale, GE Liston, WA Lyons and TN Chase. (JUL 1999). The influence of anthropogenic landscape changes on weather in south Florida. MONTHLY WEATHER REVIEW, 127(7), 1663-1673. 10.1175/1520-0493(1999)127<1663:TIOALC>2.0.CO;2
  • Chase, TN, RA Pielke, TGF Kittel, JS Baron and TJ Stohlgren. (27-Jul 1999). Potential impacts on Colorado Rocky Mountain weather due to land use changes on the adjacent Great Plains. JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 104(D14), 16673-16690. 10.1029/1999JD900118
  • Pielke, RA, J Eastman, TN Chase, J Knaff and TGF Kittel. (27-Jul 1998). 1973-1996 trends in depth-averaged tropospheric temperature. JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 103(D14), 16927-16933. 10.1029/98JD01645
  • Stohlgren, TJ, TN Chase, RA Pielke, TGF Kittel and JS Baron. (JUN 1998). Evidence that local land use practices influence regional climate, vegetation, and stream flow patterns in adjacent natural areas. GLOBAL CHANGE BIOLOGY, 4(5), 495-504. 10.1046/j.1365-2486.1998.t01-1-00182.x
  • Chase, TN, RA Pielke, TGF Kittel, R Nemani and SW Running. (20-Mar 1996). Sensitivity of a general circulation model to global changes in leaf area index. JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 101(D3), 7393-7408. 10.1029/95JD02417
  • Nemani, RR, SW Running, RA Pielke and TN CHase. (20-Mar 1996). Global vegetation cover changes from coarse resolution satellite data. JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 101(D3), 7157-7162. 10.1029/95JD02138