Monday, November 30, 2009

Silverio, 2004. Glacial cover mapping in Peru using satellite imagery

Silverio, W., J. Jaquet (2005). "Glacial cover mapping (1987-1996) of the Cordillera Blanca (Peru) using satellite imagery." Remote Sensing of the Environment 95: 342-350.

The Peruvian area has many similarities to that of the Northwest. The paper gives a good review of the natural setting and history of glacier inventories there.

-The paper notes the use of Landsat 5 images from 1987 and notes that they have a “picture element” (pixel) resolution of 28.5m but in 1996 another TM image was obtained from L7 with a pixel resolution of 30m… why had it changed? Isn’t it the same sensor? Do I need to note this stuff in my work and how do I find it out?

-The paper also discusses strong shadow effects (high relief) on the images that can be corrected through a topographic normalization using a DEM that must be 4 times the resolution of the image needing correction. Would the LiDAR DEM we have be able to help with this correction? Do we even need to worry about the correction for Hood & Rainier? They did say that the band ratio attenuates the shadow effect.

-In this paper they use NDSI using bands 2 and 5… and even reference Hall et al. 1995 but If I remember right Hall uses 4 and 5 like we are using… this is confusing to me. Why do some papers use bands 2 and 5 just as we are using 4 and 5?

-As in other studies they used color composite images to help determine glacier limits but then segmented the areas into debris free and debris covered areas and found threshold values they reported in the paper… but again, with band ratio 2 and 5.

-The paper notes that Hall says that if measurements are considered during a relatively short period (a decade or so), errors are often larger than recession of the glacier; however, if the study period is longer, uncertainty will become smaller than recession. This is something to be aware of.

A key takeaway point in the paper is that 30m pixel resolution imagery can be used for mapping of glacier recession during a period of two decades, and for a single decade with generally less accuracy.

But ultimately, I’m still confused why they were using bands 2 and 5 rather than bands 4 & 5 like we are using. It seems that most papers I’ve read use 4&5… was it a misprint? The only explanation is that he references a paper where Hall uses MODIS data but in this paper he states “TM bands”.


Colby, J. D. (1991). Topographic normalization in rugged terrain. Photogrammetric

Engineering and Remote Sensing, 57(5), 531– 537.

Dozier, J. (1989). Spectral signature of Alpine snow cover from Landsat

Thematic Mapper. Remote Sensing of Environment, 28, 9 –22.

Hall, D. (2002). Monitoring Glacier Changes from Space. http://sdcd.gsfc.

Hall, D. K., Bayr, K., Schfner, W., Bindschadler, R. A., & Chien, Y. L.

(2003). Consideration of the errors inherent in mapping historical

glacier positions in Austria from ground and space (1893–2001).

Remote Sensing of Environment, 86, 566– 577.

Hall, D. K., Riggs, G. A., & Salomonson, V. V. (1995b). Development of

methods for mapping global snow cover using Moderate Resolution

Imaging Spectroradiometer (MODIS) data. Remote Sensing of Environment,

54, 127– 140.

Hall, D. K., Chang, A. T. C., & Siddalingaiah, H. (1988). Reflectances of

glaciers as calculated using Landsat-5 Thematic Mapper Data. Remote

Sensing of Environment, 25, 311 – 321.

Hall, D. K., Ormsby, J. p., Bindschadler, R. A., & Siddalingaiah, H. (1987).

Characterization of snow and ice reflectance zones on glacier using

Landsat Thematic Mapper data. Annals of Glaciology, 9, 104– 108.

Khalsa, 2004. Space-based mapping of glacier changes using ASTER and GIS tools

Khalsa, S., M. Dyurgerov, T. Khromova, B. Raup, R. Barry. (2004). "Space-based mapping of glacier changes using ASTER and GIS tools." IEEE Transactions on Geoscience and Remote Sensing 42(10): 2177-2183.

-More than 100 million people live at n elevation within 1m of sea level.

-IPCC says will sea level will rise .5m during the 21st century, much of this will come from glaciers. Latest estimate is 27%.

-Ice and firn have lower albedo (50% or less) compared to seasonal snow (60 to 90%) so the SLA may be determined remotely.

-If measured at the end of the season the SLA is approximately coincident with the ELA, if before it may be lower.

-AAR (Accumulation Area ratio) = accumulation area/total area

-The distribution of a glaciers surface area over elevation is its hypsography.

-The annual mass balance of a glacier summed over all areas of the glacier over 1 year is a linear function of AAR.

-They digitized glacier outlines by hand based on an ASTER image using the free GLIMS software.

-They made an area-by-elevation histogram (the hypsography) for each glacier by counting the number of pixels in 50m elevation bands having a particular glacier identification. – This could be a GIS trick I could use.

-The study then uses several equations to estimate the Mass balance of glaciers using their ELA and field measurements were used to determine mass balance as a function of accumulation area ratio.

-They say that their accuracy for glacier boundaries was within 2 aster pixels (30m) but they don’t talk about debris covered ice which ASTER can’t see through… I find it strange they don’t mention such a crucial possible error in such a paper where this is well known to be a problem.

-They found that the process of volume change with elevation is not linear, but varies according to glacier hypsography.

Ultimately, this paper uses several equations to determine Mass Balance and ELA, AAR relationships but I think at least some of the input variables were field observations and it wasn’t too clear how they found the ELA/AAR from the ASTER imagery… perhaps this is something I could look back at if I begin to use ASTER imagery.


A. V. Kulkarni, “Mass balance of Himalayan glaciers using AAR and

ELA methods,” J. Glaciol., vol. 38, no. 128, pp. 101–104, 1992.

M. S. Pelto, “Mass balance of south-east Alaska and north-west British

Columbia glaciers from 1976 to 1984: Methods and results,” Ann.

Glaciol., vol. 9, pp. 189–194, 1987.

J.-P. Dedieu, A. Rabatel, C. Vincent, F. Valla, E. Thibert, and Y. Arnaud,

“Glacier mass balance determination by remote sensing in the

French Alps: Progress and limitation for time series monitoring,” in

Proc. IGARSS, Toulouse, France, July 21–25, 2003.

Thursday, November 26, 2009

Thanksgiving Cruise

Every year Emily and I head out to Sunriver or Mt. Hood with our friends to
celebrate Thanksgiving in a vacation rental with a hot tub but this year when I sent the email to over 60 people only 4 people responded which wasn’t enough to cover the cost of a vacation rental at a reasonable price... so Emily and I were left to fend for ourselves. I had been really busy with work and school projects so I kind of left it up to Em to decide what to do. She came up with a great idea... a dinner cruise on the Portland Spirit for Thanksgiving.

The cruise was really fun. We arrived in Portland early and checked into the Marriot Riverside hotel and walked down towards the Willamette stopping briefly for some coffee to kill time at Starbucks. We saw a homeless girl with her chiwawa and were going to take coffee back to her but she beat us to it stopping in to buy a coffee in order to use the bathroom. We both felt really bad for her on Thanksgiving... what could have happened to someone our age to put them on the streets on a holiday no less... maybe it was her own choosing. We walked down the pathway along the Willamette past a flock of Canadian geese until we came to our ride. On our
approach we were really hoping to see some people our age on the cruise as well and were happily
surprised to see several families and a wide range of ages. As we boarded the crew took a photo of us that we later bought because it really was a good photo of us for a change. We got a great table near the bow of the boat on the 2nd level and were treated with a piano player and a lively lyrical crew who seemed to all sing at least one Christmas carol. Our waiter was Tom and I swear he wasn’t a day older than 16 but he was very good with us. He told us he was working a double shift that day as well so I made sure to leave him a big tip. (BTW... two days ago was my last day at Ruby Tuesdays!!!... I left because I didn’t need the cash anymore or the stress, although it really was a good job while I had it). We cruised all the way down to Port Orford on the Willamette which took us from 4:30 to 7:30pm. The food was fantastic with shrimp, salmon, and the usual thanksgiving fixings as well as a roast. I pretty much gorged myself as it was all you could eat.

A bottle of wine and several drinks later we docked and headed back to the hotel for a relaxing evening with a bottle of champagne we picked up. The hotel room was super nice and it was a great holiday with just the two of us. Good job planning Emily!

Thursday, November 19, 2009

Racoviteanu, 2008. Remote Sensing of Glacial Characteristics - Debris-Covered Ice Mapping

Racoviteanu, A. M. W., R. Barry (2008). "Optical remote sensing of glacier characteristics: A review with focus on the Himalaya." Sensors 8(3356-3383).

Focus of the paper is on the potential of visible and thermal infrared remote sensing data with GIS and field methods for estimating glacial characteristics.

This study uses ASTER primarily

-Response of glaciers may also depend on ice dynamics, glacier hypsometry (the distribution of glacier area vs. elev) and topography.

-Traditional direct glacier measurements used stakes and pits at representative points on glaciers. Snow pits are also dug and thickness of the accumulation layer is determined by grain size or the presence of a layer of dirt… these methods are of course tedious with a lot of manual labor.

-Scenes aquired at the end of the ablation season are useful for identifying the end-of-summer snowline altitude (SLA) - considered to be related to variations in a glacier's mass balance and used as a surrogate for ELA on temperate glaciers. - Racoviteanu 2008.

-The thermal band of ETM+ (10.4-12.5 at 60m) and the multispectral thermal bands of ASTER (8.125-11.65 at 90m) may provide the potential for distinguishing debris-cover on glaciers. Do you know of this? Could this be possible?

-ASTER, SPOT5, IRS-1C and CORONA series can obtain stereoscopic images to monitor elevation data of the glacier surface in 3D.

-The recently launched ALOS with it’s (PRISM) sensor could provide useful data as well – this whole paragraph is about other satellite technologies that could be used but I expect they are very expensive to obtain data for.

-The paper states that ASTER imagery is available free to participants in the GLIMS project. Does our study qualify us for free ASTER Imagery?

-The Equilibrium Line Altitude (ELA)- average altitude at which accumulation balances ablation over one year. The long-term steady-state ELA is a key indicator of the health of a glacier. annual ELA's that are higher than the steady state ELA's indicate a negative mass balance for that particular year.

-Not going to note the whole description here but on page 3360 there is a great description of why each band is used to discriminate ice.

-This paper names many others which use NDSI to map glaciers and lists several threshold values found…

-Page 3361 goes into a lot detail about methods and papers that deal with mapping debris covered ice. Is this something we could look at, perhaps using the ETM+ thermal band or a thermal band from Aster combined with the liDAR DEM and a color composite image. It would be interesting to look at the possibilities. Perhaps I could come up with a method to do this for each year. I’ll take a look at this after I have all the band ratio images processed and start working on the GIS half of this research.

-Page 3362 discusses volume area scaling techniques for mass balance estimations but 3363 discusses that that the math involved may not work on smaller scale area’s with local climates like the NW and doesn’t account for debris covered ice and they assume steady state conditions which probably don’t exist on Hood or Rainier.

-Paper discusses a Geodetic approach by subtracting older DEM’s from newer ones such as the LiDAR DEM. This may be possible. But, because of uncertainties this method should only be applied on the decadal or longer time scales. Volume changes are found by multiplying the difference in elevation by the pixel size. This would be worth looking into for Hood & Rainier possibly to validate ground mass-balance calculations in other studies.

-Accumulation Area ratio/ELA methods for mass balance estimations – this looks more complicated and I would need to read more papers on these methods. This method requires in-situ measurements which I don’t know are available for Hood and Rainier. They may be from other studies.

-The paper then goes into the case study of the HImilaya.

The amount of papers and descriptive procedures for mapping debris-covered ice was the best part of this whole paper. When I start getting into the GIS portion of this research I will start to look at the possibilities of trying these methods.

Papers (He listed 136 papers.. these were the ones I thought could be useful to me)

Dyurgerov, M. Glacier Mass Balance and Regime: Data of Measurements and Analysis.

INSTAAR Occasional Paper No. 55. Institute of Arctic and Alpine Research, University of Colorado. Distributed by National Snow and Ice Data Center, Boulder, CO., 2002, updated 2005;

Dyurgerov, M.B.; Meier, M.F. Twentieth century climate change: Evidence from small

glaciers. PNAS 2000, 97 (4), 1406-1411.

Kulkarni, A.V. Mass Balance of Himalayan Glaciers Using AAR and ELA Methods. J Glaciol 1992a, 38 (128), 101-104.

Tangborn, W.; Rana, B. Mass balance and runoff of the partially debris-covered Langtang Glacier, Nepal, in: Debris-covered glaciers, A. Fountain, Eds; IAHS: Wallingsford, 2000; 264. 53 - 61.

Rees, W.G. Remote sensing of snow and ice; Taylor & Francis: 2003

Bahr, D.B. Width and length scaling of glaciers. J Glaciol 1997, 43 (145), 557-562.

Bahr, D.B.; Meier, M.F.; Peckham, S.D. The physical basis of glacier volume-area scaling. J Geophys Res B Solid Earth Planets 1997, 102 (B9), 20355-20362.

Klein, A.G.; Isacks, B.L. Glaciers: tracking change in the central Andes Mountains. GIS World 1996, 9, 48-52.

Duncan, C.C.; Klein, A.J.; Masek, J.G.; Isacks, B.L. Comparison of late Pleistocene and

modern glacier extents in central Nepal based on digital elevation data and satellite imagery. Quaternary Res 1998, 49, 241-254.

Hoelzle, M.; Haeberli, W.; Dischl, M.; Peschke, W. Secular glacier mass balances derived from

cumulative glacier length changes. Global Planet Change 2003, 36 (4), 295-306.

Dozier, J. Remote sensing of snow in the visible and near-infrared wavelengths, in: Theory and Applications of Optical Remote Sensing, G. Asrar, Eds; John Wiley and Sons: New York, 1989; 527-547.

Dozier, J. Snow reflectance from Landsat-4 Thematic Mapper. IEEE Trans Geosci Rem Sens 1984, GE-22 323-328.

Hall, D.K.; G. Riggs, A.; Salomonson, V.V. Development of methods for mapping global snow cover using moderate resolution imaging spectroradiometer data. Rem Sens Environ 1995, 54, 127-140.

Sidjak, R. Glacier mapping of the Illecillewaet icefield, British Columbia, Canada, using

Landsat TM and digital elevation data. Int J Rem Sens 1999, 20 (2), 273-284.

Dozier, J. Spectral Signature of Alpine Snow Cover from the Landsat Thematic Mapper. Rem Sens Environ 1989, 28, 9-22

Paul, F.; Huggel, C.; Kääb, A. Combining satellite multispectral image data and a digital

elevation model for mapping debris-covered glaciers. Rem Sens Environ 2004b, 89 (4), 510- 518.

Nakawo, M.; Rana, B. Estimate of ablation rate of glacier ice under a supraglacial debris layer. Geogr Ann Phys Geogr 1999, 81A (4), 695-701.

Mattson, L.E.; Gardner, J.S.; Young, G.J. Ablation on debris covered glaciers: an example from the Rakhiot Glacier, Panjab, Himalaya, in: Snow and Glacier Hydrology. Proceedings of the International Symposium, Kathmandu, Nepal, 16-21 November 1992, G.J. Young, Eds; IAHS Publication, 1993; 218.

Nakawo, M.; Morohoshi, T.; Uehara, S. Satellite data utilization for estimating ablation of debris covered glaciers, in: Snow and Glacier Hydrology. Proceedings of the International Symposium, Kathmandu, Nepal, 16-21 November 1992., G.J. Young, Eds; IAHS/AISH Publication, 1993; 218. 75-83.

Khalsa, S.J.S.; Dyurgerov, M.B.; Khromova, T.; Raup, B.H.; Barry, R.G. Space-based mapping of glacier changes using ASTER and GIS tools. IEEE Trans Geosci Rem Sens 2004, 42 (10), 2177-2183.

Bishop, M.P.; Bonk, R.; Kamp, U J.F.; Shroder, J. Terrain analysis and data modeling for

alpine glacier mapping. Polar Geogr 2001, 25 (3), 182-201.

Bolch, T.; Buchroithner, M.F.; Kunert, A.; Kamp, U. Automated delineation of debris-covered glaciers based on ASTER data. Geoinformation in Europe (Proc. of 27th EARSel Symposium, 04 -07 June 2007), Bozen, Italy 2007, 403-410.

Nakawo, M.; Yabuki, H.; Sakai, A. Characteristics of Khumbu Glacier, Nepal Himalaya: recent change in the debris-covered area. Ann Glaciol 1999, 28,118-122.

Suzuki, R.; Fujita, K.; Ageta, Y. Spatial distribution of thermal properties on debris-covered glaciers in the Himalayas derived from ASTER data. Bull Glacier Res. 2007, 24, 13-22.