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

Prashant Sardeshmukh

Research Interests

I am a climate dynamicist with broad interests in the diagnosis, modeling, and predictability of large-scale weather and climate variations around the globe on time scales of days to centuries. Our team is engaged in documenting and understanding the regional aspects of ongoing climate changes, especially changes in extreme weather statistics, and determining to what extent they are anthropogenic or consistent with natural climate variability. We are also interested in documenting and understanding the actual as well as potential skill of weather and climate predictions, which is inherently limited due to the chaotic nature of the system, and how the current prediction systems need to be improved to achieve the potential skill.

Current Research

Changing risks of extreme warm spells are not being determined by mean warming alone

It is generally presumed that global warming has increased and will continue to increase the likelihood of extreme warm temperatures almost everywhere on the globe. We find, however, using three very different types of observational datasets and model simulations of the 1959 to 2012 period that this is generally not true. While extreme warm spells indeed became more common in many regions, in many other regions their likelihood remained almost the same or even decreased from the first half to the second half of this period. The basic reason for this was a decrease of temperature variability in such regions that nearly offset and in some cases even negated the effect of the mean temperature shift on extreme temperature probabilities. The consistency of these changes among the different observational datasets and model simulations examined suggests that they are robust regional aspects of global warming associated with atmospheric circulation changes. This highlights the need for climate models to represent not just the mean regional temperature signals but also the changes in daily temperature variability associated with global warming to correctly project the changing risks of extreme hot spells into the future. (Sardeshmukh, Compo, McColl, and Penland)

Change from 1959-85 to 1986-2012 of the statistics of 5-day averaged lower tropospheric (850 hpa) temperatures in the December through February season. Change in mean (deg C, left column), standard deviation (deg C, middle column), and in the probability of exceeding an absolute extreme warm temperature threshold (defined at each location as the mean plus 2.5 standard deviations in the 1959-85 period). Results are shown for (top row) the JRA55 reanalysis dataset, (middle row) the 20th Century Reanalysis version 2c dataset, and (bottom row) an ensemble of global atmospheric general circulation model simulations with prescribed observed time-varying sea surface temperatures and sea ice and radiative forcings. Stippling shows regions where the change in the probability of extreme warm spells (A+) was less than expected from the change in the mean temperature alone (< 0.001).

View Publications

  • Dole, RM, JR Spackman, M Newman, GP Compo, CA Smith, LM Hartten, JJ Barsugli, RS Webb, MP Hoerling, R Cifelli, K Wolter, CD Barnet, M Gehne, R Gelaro, GN Kiladis, S Abbott, E Akish, J Albers, JM Brown, CJ Cox, L Darby, G de Boer, B DeLuisi, J Dias, J Dunion, J Eischeid, C Fairall, A Gambacorta, BK Gorton, A Hoell, J Intrieri, D Jackson, PE Johnston, R Lataitis, KM Mahoney, K McCaffrey, HA McColl, MJ Mueller, D Murrrray, PJ Neiman, W Otto, O Perssrssrsson, XW Quan, I Rangwala, AJ Ray, D Reynolds, ER Dellaripa, K Rosenlof, N Sakaeda, PD Sardeshmukh, LC Slivinski, L Smith, A Solomon, D Swales, S Tulich, A White, G Wick, MG Winterkorn, DE Wolfe and R Zamora (2018), ADVANCING SCIENCE AND SERVICES DURING THE 2015/16 EL NINO The NOAA El Nino Rapid Response Field Campaign. Bull. Amer. Meteorol. Soc. Version: 1 99 (5) 975-1002, issn: 0003-0007, ids: GH8CF, doi: 10.1175/BAMS-D-16-0219.1
  • Newman, M and PD Sardeshmukh (2017), Are we near the predictability limit of tropical Indo-Pacific sea surface temperatures?. Geophys. Res. Lett. Version: 1 44 (16) 8520-8529, issn: 0094-8276, ids: FG8DR, doi: 10.1002/2017GL074088
  • Capotondi, A and PD Sardeshmukh (2017), Is El Nino really changing?. Geophys. Res. Lett. Version: 1 44 (16) 8548-8556, issn: 0094-8276, ids: FG8DR, doi: 10.1002/2017GL074515
  • Giese, BS, HF Seidel, GP Compo and PD Sardeshmukh (2016), An ensemble of ocean reanalyses for 1815-2013 with sparse observational input. J. Geophys. Res.-Oceans Version: 1 121 (9) 6891-6910, issn: 2169-9275, ids: EA8TZ, doi: 10.1002/2016JC012079
  • Stucki, P, S Bronnimann, O Martius, C Welker, R Rickli, S Dierer, DN Bresch, GP Compo and PD Sardeshmukh (2015), Dynamical Downscaling and Loss Modeling for the Reconstruction of Historical Weather Extremes and Their Impacts: A Severe Foehn Storm in 1925. Bull. Amer. Meteorol. Soc. Version: 1 96 (8) , issn: 0003-0007, ids: CR5FG, doi: 10.1175/BAMS-D-14-00041.1
  • Bronnimann, S, AM Fischer, E Rozanov, P Poli, GP Compo and PD Sardeshmukh (2015), Southward shift of the northern tropical belt from 1945 to 1980. Nat. Geosci. Version: 1 8 (12) 969-U110, issn: 1752-0894, ids: CZ6GW, doi: 10.1038/NGEO2568
  • Muller, WA, D Matei, M Bersch, JH Jungclaus, H Haak, K Lohmann, GP Compo, PD Sardeshmukh and J Marotzke (2015), A twentieth-century reanalysis forced ocean model to reconstruct the North Atlantic climate variation during the 1920s. Clim. Dyn. Version: 1 44 (8-Jul) 1935-1955, issn: 0930-7575, ids: CD9YS, doi: 10.1007/s00382-014-2267-5
  • Capotondi, A and PD Sardeshmukh (2015), Optimal precursors of different types of ENSO events. Geophys. Res. Lett. Version: 1 42 (22) 9952-9960, issn: 0094-8276, ids: DB2MO, doi: 10.1002/2015GL066171
  • Sardeshmukh, PD, GP Compo and C Penland (2015), Need for Caution in Interpreting Extreme Weather Statistics. J. Clim. Version: 1 28 (23) 9166-9187, issn: 0894-8755, ids: CX7DC, doi: 10.1175/JCLI-D-15-0020.1
  • Sardeshmukh, PD and C Penland (2015), Understanding the distinctively skewed and heavy tailed character of atmospheric and oceanic probability distributions. Chaos Version: 1 25 (3) , Art. No. 36410, issn: 1054-1500, ids: CF1OB, doi: 10.1063/1.4914169, PubMed ID: 25833448
  • Sandeep, S, F Stordal, PD Sardeshmukh and GP Compo (2014), Pacific Walker Circulation variability in coupled and uncoupled climate models. Clim. Dyn. Version: 1 43 (2-Jan) 103-117, issn: 0930-7575, ids: AK3PS, doi: 10.1007/s00382-014-2135-3
  • Compo, GP, PD Sardeshmukh, JS Whitaker, P Brohan, PD Jones and C McColl (2013), Independent confirmation of global land warming without the use of station temperatures. Geophys. Res. Lett. Version: 1 40 (12) 3170-3174, issn: 0094-8276, ids: 185FJ, doi: 10.1002/grl.50425
  • Wang, XLL, Y Feng, GP Compo, VR Swail, FW Zwiers, RJ Allan and PD Sardeshmukh (2013), Trends and low frequency variability of extra-tropical cyclone activity in the ensemble of twentieth century reanalysis. Clim. Dyn. Version: 1 40 (12-Nov) 2775-2800, issn: 0930-7575, ids: 149ZU, doi: 10.1007/s00382-012-1450-9
  • Newman, M, GN Kiladis, KM Weickmann, FM Ralph and PD Sardeshmukh (2012), Relative Contributions of Synoptic and Low-Frequency Eddies to Time-Mean Atmospheric Moisture Transport, Including the Role of Atmospheric Rivers. J. Clim. Version: 1 25 (21) 7341-7361, issn: 0894-8755, ids: 036BZ, doi: 10.1175/JCLI-D-11-00665.1
  • Bronnimann, S, O Martius, H von Waldow, C Welker, J Luterbacher, GP Compo, PD Sardeshmukh and T Usbeck (2012), Extreme winds at northern mid-latitudes since 1871. Meteorol. Z. Version: 1 21 (1) 13-27, issn: 0941-2948, ids: 906XQ, doi: 10.1127/0941-2948/2012/0337
  • Penland, C and PD Sardeshmukh (2012), Alternative interpretations of power-law distributions found in nature. Chaos Version: 1 22 (2) , Art. No. 23119, issn: 1054-1500, ids: 966JM, doi: 10.1063/1.4706504, PubMed ID: 22757526
  • Shin, SI and PD Sardeshmukh (2011), Critical influence of the pattern of Tropical Ocean warming on remote climate trends. Clim. Dyn. Version: 1 36 (8-Jul) 1577-1591, issn: 0930-7575, ids: 744PA, doi: 10.1007/s00382-009-0732-3
  • Pegion, K and PD Sardeshmukh (2011), Prospects for Improving Subseasonal Predictions. Mon. Weather Rev. Version: 1 139 (11) 3648-3666, issn: 0027-0644, ids: 840XP, doi: 10.1175/MWR-D-11-00004.1
  • Compo, GP, JS Whitaker, PD Sardeshmukh, N Matsui, RJ Allan, X Yin, BE Gleason, RS Vose, G Rutledge, P Bessemoulin, S Bronnimann, M Brunet, RI Crouthamel, AN Grant, PY Groisman, PD Jones, MC Kruk, AC Kruger, GJ Marshall, M Maugeri, HY Mok, O Nordli, TF Ross, RM Trigo, XL Wang, SD Woodruff and SJ Worley (2011), The Twentieth Century Reanalysis Project. Q. J. R. Meteorol. Soc. Version: 1 137 (654) 1-28, issn: 0035-9009, ids: 724QX, doi: 10.1002/qj.776
  • Shin, SI, PD Sardeshmukh and SW Yeh (2011), Sensitivity of the northeast Asian summer monsoon to tropical sea surface temperatures. Geophys. Res. Lett. Version: 1 38 , Art. No. L22702, issn: 0094-8276, ids: 851HH, doi: 10.1029/2011GL049391
  • Wang, XLL, H Wan, FW Zwiers, VR Swail, GP Compo, RJ Allan, RS Vose, S Jourdain and XG Yin (2011), Trends and low-frequency variability of storminess over western Europe, 1878-2007. Clim. Dyn. Version: 1 37 (12-Nov) 2355-2371, issn: 0930-7575, ids: 852GU, doi: 10.1007/s00382-011-1107-0
  • Compo, GP and PD Sardeshmukh (2010), Removing ENSO-Related Variations from the Climate Record. J. Clim. Version: 1 23 (8) 1957-1978, issn: 0894-8755, ids: 594LE, doi: 10.1175/2009JCLI2735.1
  • Shin, SI, PD Sardeshmukh and K Pegion (2010), Realism of local and remote feedbacks on tropical sea surface temperatures in climate models. J. Geophys. Res.-Atmos. Version: 1 115 , Art. No. D21110, issn: 2169-897X, ids: 676UT, doi: 10.1029/2010JD013927
  • Shin, SI, PD Sardeshmukh and RS Webb (2010), Optimal Tropical Sea Surface Temperature Forcing of North American Drought. J. Clim. Version: 1 23 (14) 3907-3917, issn: 0894-8755, ids: 643FK, doi: 10.1175/2010JCLI3360.1
  • Giese, BS, GP Compo, NC Slowey, PD Sardeshmukh, JA Carton, S Ray and JS Whitaker (2010), THE 1918/19 EL NINO. Bull. Amer. Meteorol. Soc. Version: 1 91 (2) 177-183, issn: 0003-0007, ids: 572XH, doi: 10.1175/2009BAMS2903.1
  • Sardeshmukh, PD and P Sura (2009), Reconciling Non-Gaussian Climate Statistics with Linear Dynamics. J. Clim. Version: 1 22 (5) 1193-1207, issn: 0894-8755, ids: 426AZ, doi: 10.1175/2008JCLI2358.1
  • Sura, P and PD Sardeshmukh (2009), A global view of air-sea thermal coupling and related non-Gaussian SST variability. Atmos. Res. Version: 1 Special Session on Ocean-Atmosphere Coupling held at the 24th IUGG 94 (1) 140-149, Perugia, ITALY, JUL 02-12, 2007, issn: 0169-8095, ids: 496HR, doi: 10.1016/j.atmosres.2008.08.008
  • Compo, GP and PD Sardeshmukh (2009), Oceanic influences on recent continental warming. Clim. Dyn. Version: 1 32 (3-Feb) 333-342, issn: 0930-7575, ids: 389IO, doi: 10.1007/s00382-008-0448-9
  • Newman, M, PD Sardeshmukh and C Penland (2009), How Important Is Air-Sea Coupling in ENSO and MJO Evolution?. J. Clim. Version: 1 22 (11) 2958-2977, issn: 0894-8755, ids: 467SR, doi: 10.1175/2008JCLI2659.1
  • Newman, M and PD Sardeshmukh (2008), Tropical and stratospheric influences on extratropical short-term climate variability. J. Clim. Version: 1 21 (17) 4326-4347, issn: 0894-8755, ids: 345JC, doi: 10.1175/2008JCLI2118.1
  • Sura, P and PD Sardeshmukh (2008), A Global view of non-Gaussian SST variability. J. Phys. Oceanogr. Version: 1 38 (3) 639-647, issn: 0022-3670, ids: 276EQ, doi: 10.1175/2007JPO3761.1
  • Sardeshmukh, PD and P Sura (2007), Multiscale impacts of variable heating in climate. J. Clim. Version: 1 20 (23) 5677-5695, issn: 0894-8755, ids: 239RG, doi: 10.1175/2007JCLI1411.1
  • Compo, GP, JS Whitaker and PD Sardeshmukh (2006), Feasibility of a 100-year reanalysis using only surface pressure data. Bull. Amer. Meteorol. Soc. Version: 1 87 (2) 175-+, issn: 0003-0007, ids: 021CW, doi: 10.1175/BAMS-87-2-175
  • Barsugli, JJ, SI Shin and PD Sardeshmukh (2006), Sensitivity of global warming to the pattern of tropical ocean warming. Clim. Dyn. Version: 1 27 (5) 483-492, issn: 0930-7575, ids: 076KM, doi: 10.1007/s00382-006-0143-7
  • Shin, SI, PD Sardeshmukh, RS Webb, RJ Oglesby and JJ Barsugli (2006), Understanding the mid-Holocene climate. J. Clim. Version: 1 19 (12) 2801-2817, issn: 0894-8755, ids: 057ZT, doi: 10.1175/JCLI3733.1
  • Barsugli, J, SI Shin and PD Sardeshmukh (2005), Tropical climate regimes and global climate sensitivity in a simple setting. J. Atmos. Sci. Version: 1 62 (4) 1226-1240, issn: 0022-4928, ids: 918EL, doi: 10.1175/JAS3404.1
  • Sura, P, M Newman, C Penland and P Sardeshmukh (2005), Multiplicative noise and non-gaussianity: A paradigm for atmospheric regimes?. J. Atmos. Sci. Version: 1 62 (5) 1391-1409, issn: 0022-4928, ids: 929IB, doi: 10.1175/JAS3408.1
  • Compo, GP and PD Sardeshmukh (2004), Storm track predictability on seasonal and decadal scales. J. Clim. Version: 1 17 (19) 3701-3720, issn: 0894-8755, ids: 860RZ, doi: 10.1175/1520-0442(2004)017<3701:STPOSA>2.0.CO;2
  • Bergman, JW and PD Sardeshmukh (2004), Dynamic stabilization of atmospheric single column models. J. Clim. Version: 1 17 (5) 1004-1021, issn: 0894-8755, ids: 801RX, doi: 10.1175/1520-0442(2004)017<1004:DSOASC>2.0.CO;2
  • Sardeshmukh, PD, C Penland and M Newman (2003), Drifts induced by multiplicative red noise with application to climate. Europhys. Lett. Version: 1 63 (4) 498-504, issn: 0295-5075, ids: 709GU, doi: 10.1209/epl/i2003-00550-y
  • Bergman, JW and PD Sardeshmukh (2003), Usefulness of single column model diagnosis through short-term predictions. J. Clim. Version: 1 16 (22) 3803-3819, issn: 0894-8755, ids: 742MT, doi: 10.1175/1520-0442(2003)016<3803:UOSCMD>2.0.CO;2
  • Newman, M, PD Sardeshmukh, CR Winkler and JS Whitaker (2003), A study of subseasonal predictability. Mon. Weather Rev. Version: 1 131 (8) 1715-1732, issn: 0027-0644, ids: 704NY, doi: 10.1175//2558.1
  • Barsugli, JJ and PD Sardeshmukh (2002), Global atmospheric sensitivity to tropical SST anomalies throughout the Indo-Pacific basin. J. Clim. Version: 1 15 (23) 3427-3442, issn: 0894-8755, ids: 615WH, doi: 10.1175/1520-0442(2002)015<3427:GASTTS>2.0.CO;2
  • Ricciardulli, L and PD Sardeshmukh (2002), Local time- and space scales of organized tropical deep convection. J. Clim. Version: 1 15 (19) 2775-2790, issn: 0894-8755, ids: 593RQ, doi: 10.1175/1520-0442(2002)015<2775:LTASSO>2.0.CO;2
  • Compo, GP, PD Sardeshmukh and C Penland (2001), Changes of subseasonal variability associated with El Nino. J. Clim. Version: 1 14 (16) 3356-3374, issn: 0894-8755, ids: 464WF, doi: 10.1175/1520-0442(2001)014<3356:COSVAW>2.0.CO;2
  • Winkler, CR, M Newman and PD Sardeshmukh (2001), A linear model of wintertime low-frequency variability. Part I: Formulation and forecast skill. J. Clim. Version: 1 14 (24) 4474-4494, issn: 0894-8755, ids: 504XE, doi: 10.1175/1520-0442(2001)014<4474:ALMOWL>2.0.CO;2
  • Sardeshmukh, PD, GP Compo and C Penland (2000), Changes of probability associated with El Nino. J. Clim. Version: 1 13 (24) 4268-4286, issn: 0894-8755, ids: 385EF, doi: 10.1175/1520-0442(2000)013<4268:COPAWE>2.0.CO;2
  • Huang, HP and PD Sardeshmukh (2000), Another look at the annual and semiannual cycles of atmospheric angular momentum. J. Clim. Version: 1 13 (18) 3221-3238, issn: 0894-8755, ids: 364MN, doi: 10.1175/1520-0442(2000)013<3221:ALATAA>2.0.CO;2
  • Newman, M, PD Sardeshmukh and JW Bergman (2000), An assessment of the NCEP, NASA, and ECMWF reanalyses over the tropical west Pacific warm pool. Bull. Amer. Meteorol. Soc. Version: 1 81 (1) 41-48, issn: 0003-0007, ids: 270GT, doi: 10.1175/1520-0477(2000)081<0041:AAOTNN>2.3.CO;2
  • Smith, CA and PD Sardeshmukh (2000), The effect of ENSO on the intraseasonal variance of surface temperatures in winter. Int. J. Climatol. Version: 1 20 (13) 1543-1557, issn: 0899-8418, ids: 376EP, doi: 10.1002/1097-0088(20001115)20:13<1543::AID-JOC579>3.0.CO;2-A
  • Hall, NMJ and PD Sardeshmukh (1998), Is the time-mean northern hemisphere flow baroclinically unstable?. J. Atmos. Sci. Version: 1 55 (1) 41-56, issn: 0022-4928, ids: YQ943, doi: 10.1175/1520-0469(1998)055<0041:ITTMNH>2.0.CO;2
  • Newman, M and PD Sardeshmukh (1998), The impact of the annual cycle on the North Pacific North American response to remote low-frequency forcing. J. Atmos. Sci. Version: 1 55 (8) 1336-1353, issn: 0022-4928, ids: ZJ701, doi: 10.1175/1520-0469(1998)055<1336:TIOTAC>2.0.CO;2
  • Whitaker, JS and PD Sardeshmukh (1998), A linear theory of extratropical synoptic eddy statistics. J. Atmos. Sci. Version: 1 55 (2) 237-258, issn: 0022-4928, ids: YT205, doi: 10.1175/1520-0469(1998)055<0237:ALTOES>2.0.CO;2
  • KLINKER, E and PD SARDESHMUKH (1992), THE DIAGNOSIS OF MECHANICAL DISSIPATION IN THE ATMOSPHERE FROM LARGE-SCALE BALANCE REQUIREMENTS. J. Atmos. Sci. Version: 1 49 (7) 608-627, issn: 0022-4928, ids: HQ272, doi: 10.1175/1520-0469(1992)049<0608:TDOMDI>2.0.CO;2