I’m a field hydrologist, interested in the role of snow in the hydrological cycle, and how this is changing with ongoing climate change and global warming. Niigata and most of northern Japan currently depend on abundant snowmelt during the spring season for rice paddy irrigation, but how much snowmelt will there be in a warmer climate? This is one of the important questions that I address in my teaching and research.
1. Influence of climate change on the hydrological regime in headwater basins
Global warming will lead to winters with less snow and more rain in maritime areas such as Niigata. Climate change scenarios published by IPCC show a likely winter warming of 2-3°C by 2100, which means a much smaller spring snowpack and much less snowmelt during the irrigation season. I’m using hydrological and snowmelt modelling techniques to assess the likely changes in the seasonal flows of rivers due to climate change.
2. Estimation of snowpack water and energy balance under forest canopies
Forest canopies strongly control the water and energy balance of the snowpack, which in turn determines the amount and rate of snowmelt, and streamflow. We also manage the forest in ways that change dramatically the nature of the forest canopy. What happens to snow caught in the forest canopy, and how is the water and energy balance different between species? These are some of the questions I’m researching through fieldwork in northern Niigata Prefecture.
3. Suspended sediment and bed load dynamics in gravel bed streams
Rivers carry not only water but also much sediment during times of heavy rainfall or snowmelt. Suspended sediment and bed load are deposited downstream on river flood plains or behind dams. Monitoring sediment processes in the Takiya River, we have tracked changes of great magnitude after the occurrence of extreme summer floods. I’m interested in how extreme rainfall and flooding triggers changes in sediment supply dynamics, leading to channel change and instability.
1. Park, S.-E., Yamaguchi, Y., Singh, G., Yamaguchi, S., Whitaker, A.C. (2014). Polarimetric SAR Response of Snow-Covered Area Observed by Multi-Temporal ALOS PALSAR Fully Polarimetric Mode. IEEE Transactions on Geoscience and Remote Sensing 52(1), 329-340. DOI: 10.1109/TGRS.2013.2240000.
2. Whitaker, A.C., A. Yoshimura (2012). Climate change impacts on the seasonal distribution of runoff in a snowy headwater basin, Niigata. Hydrological Research Letters 6, 7-12. DOI: 10.3178/HRL.6.7.
3. Whitaker, A.C., H. Sato and H. Sugiyama (2008). Changing suspended sediment dynamics due to extreme flood events in a small pluvial-nival system in northern Japan. In: Sediment Dynamics in Changing Environments (Proceedings of symposium held in Christchurch, New Zealand, December 2008). IAHS Publ. 325, 192-199.
4. Whitaker, A.C., H. Sugiyama and K. Hayakawa (2008). Effect of snow cover conditions on the hydrologic regime: case study in a pluvial-nival watershed, Japan. J. of American Water Resources Association (JAWRA) 44(4):814-828. DOI: 10.1111/j.1752-1688.2008.00206.x.
5. Whitaker, A.C., and D.F. Potts (2007). Coarse bed load transport in an alluvial gravel bed stream, Dupuyer Creek, Montana. Earth Surface Processes and Landforms 32(13), 1984-2004. DOI: 10.1002/esp.1512.
6. Whitaker, A.C., and D.F. Potts (2007). Analysis of flow competence in an alluvial gravel bed stream, Dupuyer Creek, Montana. Water Resources Research 43, W07433. DOI:10.1029/2006WR005289.
7. Whitaker, A.C., and H. Sugiyama (2005). Seasonal snowpack dynamics and runoff in a cool temperate forest: lysimeter experiment in Niigata, Japan. Hydrological Processes 19, 4179-4200. DOI: 10.1002/hyp.6059.
- Takiya River, Niigatahttps://takiya-river.blogspot.jp/