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

Richard Armstrong

Research Interests

In general my interests cover a wide range of snow and glacier topics, from snow metamorphism to avalanches and glacier mass balance and glacier area and mass change in response to a warming climate. Methodologies include both in situ and satellite data. Current focus is on determining how much river discharge originates as melting seasonal snow and how much as melting glacier ice across High Asia, the CHARIS project. This distinction is important because while seasonal snow cover returns every year, albeit in varying amounts, glaciers disappear as a result of a warming climate—and that water source is totally lost for the current era.

Current Research

Establishing a Collaborative Effort to Assess the Role of Glaciers and Seasonal Snow Cover in the Hydrology of the Mountains of High Asia -The USAID-funded CHARIS project:

Across the five full basins of the CHARIS study (east-to-west, Brahmaputra, Ganges, Indus, Amu Darya, Syr Darya) the annual contribution to river discharge from melting glacier ice for the period 2010 to 2015 averages around 1%.  However, the contribution from seasonal snow cover ranges from approximately 40% in the west (Indus, Amu Darya, Syr Darya) to approximately 30% for the Brahmaputra and 5% for the Ganges (see figure 1.) The remaining river discharge results from rainfall and ground water. Within the 3,000- to 6,000-meter elevation band the contribution of glacier ice slightly exceeds 1% in the east increasing to approximately 5% in the west.  The contribution from seasonal snow cover within this elevation band ranges from approximately 65% to 75% in the Indus, Amu Darya, Syr Darya, and Brahmaputra to approximately 40% for the Ganges. Melt from glacier ice makes a significant contribution only during the months of June, July, and August. During these summer months in the Ganges and Brahmaputra the river discharge is dominated by monsoon rainfall. In summary, glacier melt water contributes greatest to river discharge in the countries considered most vulnerable to drought, for example Pakistan and Afghanistan, and therefore glacier melt serves as a buffer against drought following winters with less than normal snowfall combined with lack of summer rain.  While slow glacier retreat is being observed in the east, glaciers appear to be more stable in the west (higher elevation and higher latitude than the east), and the seasonal snow cover does not show a statistically significant reduction over the past 15 years in the west.

The CHARIS project has established collaborative partnerships with 11 institutions in 8 countries (Bhutan, Nepal, India, Pakistan, Afghanistan, Kyrgyzstan, Tajikistan, Kazakhstan). These partnerships provide a two-fold benefit through both capacity building and sharing of in-situ field data with University of Colorado researchers.  A total of 9 training workshops for partners have been conducted by CU staff over the past 5 years covering the topics of fundamental glaciology, digital elevation models (DEMs), geographic information systems (GIS), satellite data applications, mountain hydrology, water chemistry, snow cover and glacier mapping and melt modeling. These partnerships promote and facilitate the international cooperation required for successful cross-boundary water resources management on a regional, not just a national basis.

Map showing snow, ice and rainfall in CHARIS basins

Figure 1: Mean annual melt contribution of snow, ice and rainfall to runoff in full CHARIS basins – 2001-2014.

View Publications

  • Khan, AL; Rittger, K; Xian, P; Katich, JM; Armstrong, RL; Kayastha, RB; Dana, JL; McKnight, DM (2020), Biofuel Burning Influences Refractory Black Carbon Concentrations in Seasonal Snow at Lower Elevations of the Dudh Koshi River Basin of Nepal. Version: 1 FRONTIERS IN EARTH SCIENCE 8 , Art. No. 371, doi: 10.3389/feart.2020.00371
  • Racoviteanu, AE; Rittger, K; Armstrong, R (2019), An Automated Approach for Estimating Snowline Altitudes in the Karakoram and Eastern Himalaya From Remote Sensing. Version: 1 FRONTIERS IN EARTH SCIENCE 7 , Art. No. UNSP 220, doi: 10.3389/feart.2019.00220
  • Armstrong, RL; Rittger, K; Brodzik, MJ; Racoviteanu, A; Barrett, AP; Khalsa, SJS; Raup, B; Hill, AF; Khan, AL; Wilson, AM; Kayastha, RB; Fetterer, F; Armstrong, B (2019), Runoff from glacier ice and seasonal snow in High Asia: separating melt water sources in river flow. REGIONAL ENVIRONMENTAL CHANGE Version: 1 19 (5) 1249-1261, issn: 1436-3798, doi: doi: 10.1007/s10113-018-1429-0
  • Armstrong, RL; Rittger, K; Brodzik, MJ; Racoviteanu, A; Barrett, AP; Khalsa, SJS; Raup, B; Hill, AF; Khan, AL; Wilson, AM; Kayastha, RB; Fetterer, F; Armstrong, B (2019), Runoff from glacier ice and seasonal snow in High Asia: separating melt water sources in river flow. Version: 1 REGIONAL ENVIRONMENTAL CHANGE 19 (5) 1249-1261, issn: 1436-3798, doi: 10.1007/s10113-018-1429-0
  • Khan, AL, S Wagner, R Jaffe, P Xian, M Williams, R Armstrong and D McKnight (2017), Dissolved black carbon in the global cryosphere: Concentrations and chemical signatures. Geophys. Res. Lett. Version: 1 44 (12) 6226-6234, issn: 0094-8276, ids: FB0SG, doi: 10.1002/2017GL073485
  • Wilson, AM, S Gladfelter, MW Williams, S Shahi, P Baral, R Armstrong and A Racoviteanu (2017), High Asia: The International Dynamics of Climate Change and Water Security. J. Asian Stud. Version: 1 Catastrophic Asia Spring Symposium 76 (2) 457-480, Univ Colorado Boulder, Boulder, CO, APR, 2014, issn: 0021-9118, ids: EY2DC, doi: 10.1017/S0021911817000092
  • Normatov, PI, R Armstrong and IS Normatov (2016), Variations in hydrological parameters of the Zeravshan River and its tributaries depending on meteorological conditions. Russ. Meteorol. Hydrol. Version: 1 41 (9) 657-661, issn: 1068-3739, ids: EA4WA, doi: 10.3103/S1068373916090090
  • Severskiy, I, E Vilesov, R Armstrong, A Kokarev, L Kogutenko, Z Usmanova, V Morozova and B Raup (2016), Changes in glaciation of the Balkhash-Alakol basin, central Asia, over recent decades. Ann. Glaciol. Version: 1 International Symposium on Glaciology in High Mountain Asia (HMA) 57 (71) 382-394, Kathmandu, NEPAL, MAR, 2015, issn: 0260-3055, ids: DY1YY, doi: 10.3189/2016AoG71A575
  • Eakins, BW, ML Bohan, AA Armstrong, M Westington, J Jencks, E Lim, SJ McLean and RR Warnken (2015), NOAAs Role in Defining the US Extended Continental Shelf. Mar. Technol. Soc. J. Version: 1 49 (2) 204-210, issn: 0025-3324, ids: CI9BD, doi: 10.4031/MTSJ.49.2.17
  • Racoviteanu, AE, R Armstrong and MW Williams (2013), Evaluation of an ice ablation model to estimate the contribution of melting glacier ice to annual discharge in the Nepal Himalaya. Water Resour. Res. Version: 1 49 (9) 5117-5133, issn: 0043-1397, ids: 238ZO, doi: 10.1002/wrcr.20370
  • Painter, TH, MJ Brodzik, A Racoviteanu and R Armstrong (2012), Automated mapping of Earth's annual minimum exposed snow and ice with MODIS. Geophys. Res. Lett. Version: 1 39 , Art. No. L20501, issn: 0094-8276, ids: 027IH, doi: 10.1029/2012GL053340
  • Racoviteanu, AE, F Paul, B Raup, SJS Khalsa and R Armstrong (2009), Challenges and recommendations in mapping of glacier parameters from space: results of the 2008 Global Land Ice Measurements from Space (GLIMS) workshop, Boulder, Colorado, USA. Ann. Glaciol. Version: 1 50 (53) 53-69, issn: 0260-3055, ids: 628HM, doi: 10.3189/172756410790595804
  • Savoie, MH, RL Armstrong, MJ Brodzik and JR Wang (2009), Atmospheric corrections for improved satellite passive microwave snow cover retrievals over the Tibet Plateau. Remote Sens. Environ. Version: 1 113 (12) 2661-2669, issn: 0034-4257, ids: 519MS, doi: 10.1016/j.rse.2009.08.006
  • Tedesco, M, M Brodzik, R Armstrong, M Savoie and J Ramage (2009), Pan arctic terrestrial snowmelt trends (1979-2008) from spaceborne passive microwave data and correlation with the Arctic Oscillation. Geophys. Res. Lett. Version: 1 36 , Art. No. L21402, issn: 0094-8276, ids: 516YL, doi: 10.1029/2009GL039672
  • Elder, K, D Cline, GE Liston and R Armstrong (2009), NASA Cold Land Processes Experiment (CLPX 2002/03): Field Measurements of Snowpack Properties and Soil Moisture. J. Hydrometeorol. Version: 1 10 (1) 320-329, issn: 1525-755X, ids: 414GX, doi: 10.1175/2008JHM877.1
  • Yang, DQ, YY Zhao, R Armstrong and D Robinson (2009), Yukon River streamflow response to seasonal snow cover changes. Hydrol. Process. Version: 1 23 (1) 109-121, issn: 0885-6087, ids: 393TX, doi: 10.1002/hyp.7216
  • Beedle, MJ, M Dyurgerov, W Tangborn, SJS Khalsa, C Helm, B Raup, R Armstrong and RG Barry (2008), Improving estimation of glacier volume change: a GLIMS case study of Bering Glacier System, Alaska. Cryosphere Version: 1 2 (1) 33-51, issn: 1994-0416, ids: V11AS, doi: 10.5194/tc-2-33-2008
  • Davis, RE, TH Painter, D Cline, R Armstrong, T Haran, K McDonald, R Forster and K Elder (2008), NASA Cold Land Processes Experiment (CLPX 2002/03): Spaceborne Remote Sensing. J. Hydrometeorol. Version: 1 9 (6) 1427-1433, issn: 1525-755X, ids: 386DD, doi: 10.1175/2008JHM926.1
  • Donlon, C, I Robinson, KS Casey, J Vazquez-Cuervo, E Armstrong, O Arino, C Gentemann, D May, P LeBorgne, J Piolle, I Barton, H Beggs, DJS Poulter, CJ Merchant, A Bingham, S Heinz, A Harris, G Wick, B Emery, P Minnett, R Evans, D Llewellyn-Jones, C Mutlow, RW Reynolds, H Kawamura and N Rayner (2007), The global ocean data assimilation experiment high-resolution sea surface temperature pilot project. Bull. Amer. Meteorol. Soc. Version: 1 88 (8) 1197-1213, issn: 0003-0007, ids: 205LA, doi: 10.1175/BAMS-88-8-1197
  • Yang, DQ, YY Zhao, R Armstrong, D Robinson and MJ Brodzik (2007), Streamflow response to seasonal snow cover mass changes over large Siberian watersheds. J. Geophys. Res.-Earth Surf. Version: 1 112 (F2) , Art. No. F02S22, issn: 0148-0227, ids: 168BG, doi: 10.1029/2006JF000518
  • Raup, B, A Racoviteanu, SJS Khalsa, C Helm, R Armstrong and Y Arnaud (2007), The GLIMS geospatial glacier database: A new tool for studying glacier change. Glob. Planet. Change Version: 1 56 (2-Jan) 101-110, issn: 0921-8181, ids: 149FC, doi: 10.1016/j.gloplacha.2006.07.018
  • Jefferies, SM, SW McIntosh, JD Armstrong, TJ Bogdan, A Cacciani and B Fleck (2006), Magnetoacoustic portals and the basal heating of the solar chromosphere. Astrophys. J. Version: 1 648 Part 2 (2) L151-L155, issn: 0004-637X, ids: 082RB
  • Tedesco, M, EJ Kim, D Cline, T Graf, T Koike, R Armstrong, MJ Brodzik and J Hardy (2006), Comparison of local scale measured and modelled brightness temperatures and snow parameters from the CLPX 2003 by means of a dense medium radiative transfer theory model. Hydrol. Process. Version: 1 62nd Eastern Snow Conference (ESC) 20 (4) 657-672, Waterloo, CANADA, JUN 07-10, 2005, issn: 0885-6087, ids: 026IK, doi: 10.1002/hyp.6129
  • Foster, J, R Kelly, A Rango, R Armstrong, EF Erbe, C Pooley and WP Wergin (2006), Use of low-temperature scanning electron microscopy to compare and characterize three classes of snow cover. Scanning Version: 1 28 (4) 191-203, issn: 0161-0457, ids: 076JC, doi: 10.1002/sca.4950280401, PubMed ID: 16898666
  • Chang, ATC, REJ Kelly, EG Josberger, RL Armstrong, JL Foster and NM Mognard (2005), Analysis of ground-measured and passive-microwave-derived snow depth variations in midwinter across the northern Great Plains. J. Hydrometeorol. Version: 1 6 (1) 20-33, issn: 1525-755X, ids: 903OT, doi: 10.1175/JHM-405.1
  • Zhang, T, RL Armstrong and J Smith (2003), Investigation of the near-surface soil freeze-thaw cycle in the contiguous United States: Algorithm development and validation. J. Geophys. Res.-Atmos. Version: 1 108 (D22) , Art. No. 8860, issn: 2169-897X, ids: 744VQ, doi: 10.1029/2003JD003530
  • Oelke, C, TJ Zhang, MC Serreze and RL Armstrong (2003), Regional-scale modeling of soil freeze/thaw over the Arctic drainage basin. J. Geophys. Res.-Atmos. Version: 1 108 (D10) , Art. No. 4314, issn: 2169-897X, ids: 686CM, doi: 10.1029/2002JD002722
  • Armstrong, RL and MJ Brodzik (2002), Hemispheric-scale comparison and evaluation of passive-microwave snow algorithms. Version: 1 ANNALS OF GLACIOLOGY, VOL 34, 2002 4th International Symposium on Remote Sensing in Glaciology 34 38-44, UNIV MARYLAND, COLLEGE PK, MD, JUN 03-08, 2001, Ed. Winther, JG; Solberg, R, issn: 0260-3055, ids: BU99C, isbn: 0-946417-29-6, doi: 10.3189/172756402781817428
  • Frei, A, RL Armstrong, MP Clark and MC Serreze (2002), Catskill mountain water resources: Vulnerability, hydroclimatology, and climate-change sensitivity. Ann. Assoc. Am. Geogr. Version: 1 92 (2) 203-224, issn: 0004-5608, ids: 565YT, doi: 10.1111/1467-8306.00287
  • Zhang, T and RL Armstrong (2001), Soil freeze/thaw cycles over snow-free land detected by passive microwave remote sensing. Geophys. Res. Lett. Version: 1 28 (5) 763-766, issn: 0094-8276, ids: 406RV, doi: 10.1029/2000GL011952
  • Armstrong, RL and MJ Brodzik (2001), Recent Northern Hemisphere snow extent: A comparison of data derived from visible and microwave satellite sensors. Geophys. Res. Lett. Version: 1 28 (19) 3673-3676, issn: 0094-8276, ids: 476GF, doi: 10.1029/2000GL012556
  • Tait, AB, DK Hall, JL Foster and RL Armstrong (2000), Utilizing multiple datasets for snow-cover mapping. Remote Sens. Environ. Version: 1 72 (1) 111-126, issn: 0034-4257, ids: 295CF, doi: 10.1016/S0034-4257(99)00099-1
  • Serreze, MC, MP Clark, RL Armstrong, DA McGinnis and RS Pulwarty (1999), Characteristics of the western United States snowpack from snowpack telemetry (SNOTEL) data. Water Resour. Res. Version: 1 35 (7) 2145-2160, issn: 0043-1397, ids: 211DV, doi: 10.1029/1999WR900090
  • Meier, MF, R Armstrong and MB Dyurgerov (1997), Annual net balance of north cascade glaciers, 1984-94 - Comment. J. Glaciol. Version: 1 43 (143) 192-193, issn: 0022-1430, ids: XK646
  • ARMSTRONG, RL and MJ BRODZIK (1995), AN EARTH-GRIDDED SSM/I DATA SET FOR CRYOSPHERIC STUDIES AND GLOBAL CHANGE MONITORING. Version: 1 SATELLITE MONITORING OF THE EARTHS SURFACE AND ATMOSPHERE A1 Symposium of COSPAR Scientific Commission A on Satellite Monitoring of the Earths Surface and Atmosphere, at the 13th COSPAR Scientific Assembly 16 (10) 155-163, HAMBURG, GERMANY, JUL 11-21, 1994, Ed. Arnault, S, issn: 0273-1177, ids: BD15W, isbn: 0-08-042635-2, doi: 10.1016/0273-1177(95)00397-W
  • Barry, RG, JM Fallot and RL Armstrong (1995), Twentieth-century variability in snow-cover conditions and approaches to detecting and monitoring changes: Status and prospects. Prog. Phys. Geogr. Version: 1 19 (4) 520-532, issn: 0309-1333, ids: TK679, doi: 10.1177/030913339501900405
  • MCCLUNG, DM and RL ARMSTRONG (1993), TEMPERATE GLACIER TIME RESPONSE FROM FIELD DATA. J. Glaciol. Version: 1 39 (132) 323-326, issn: 0022-1430, ids: MK676, doi: 10.3189/S0022143000015987
  • BARRY, RG and RL ARMSTRONG (1990), GLACIOLOGY. Geotimes Version: 1 35 (2) 58-59, issn: 0016-8556, ids: CP979
  • BARRY, RG and RL ARMSTRONG (1987), SNOW COVER DATA MANAGEMENT - THE ROLE OF WDC-A FOR GLACIOLOGY. Hydrol. Sci. J.-J. Sci. Hydrol. Version: 1 32 (3) 281-295, issn: 0262-6667, ids: J9360, doi: 10.1080/02626668709491189