uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Large-scale runoff routing with an aggregated network-response function
Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL. (Hydrologi)
Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL. (Hydrologi)
Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL. (Hydrologi)
Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL. (Hydrologi)
2009 (English)In: Journal of Hydrology, ISSN 0022-1694, E-ISSN 1879-2707, Vol. 368, no 1-4, 237-250 p.Article in journal (Refereed) Published
Abstract [en]

The accuracy of runoff routing for global water-balance models and land-surface schemes is limited by the low spatial resolution of flow networks. Many such networks have been developed for specific models at specific spatial resolutions. However, although low-resolution networks can be derived by up-scaling algorithms from high-resolution datasets, such low-resolution networks are inherently incoherent, and slight differences in their spatial resolution can cause significant deviations in routing dynamics. By neglecting convective delay, storage-based routing algorithms produce artificially early arriving peaks on large scales. A theoretical comparison between a diffusion-wave-routing algorithm and linear-reservoir-routing (LRR) algorithm on a 30-km cell demonstrated that the commonly used LRR method consistently underestimates the travel time through the cells. A new aggregated network-response-function (NRF) routing algorithm was proposed in this study and evaluated against a conventional flow-net-based cell-to-cell LRR algorithm. The evaluation was done for the 25,325 km(2) Dongjiang (East River) basin, a tributary to the Pearl River in southern China well equipped with hydrological and meteorological stations. The NRF method transfers high-resolution delay dynamics, instead of networks, to any lower spatial resolution where runoff is generated. It preserves, over all scales, the spatially distributed time-delay information in the 1-km HYDRO1k flow network in the form of simple cell-response functions for any low-resolution grid. The NRF routing was shown to be scale independent for latitude-longitude resolutions ranging from 5’ to 1 degrees. This scale independency allowed a study of input heterogeneity on modelled discharge modelled with a daily version of the WASMOD-M water-balance model. The model efficiency of WASMOD-M-generated daily discharge at the Boluo gauging station in the Dongjiang basin in south China was constantly high (0.89) within the whole range of resolutions when routed by the NRF algorithm. The performance dropped sharply for decreasing resolution when runoff was routed with the LRR method. The three WASMOD-M parameters were scale independent in combination with NRF, but not with LRR, and the same parameter values gave equally good results at all spatial resolutions. The effect of spatial resolution on the routing delay was much more important than the spatial variability of the climate-input field for scales ranging from 5’ to 1 degrees. The extra information in a distributed versus a uniform climate input could only be used when the NRF method was used to route the runoff. NRF requires more labour than LRR to set up but the model performance is very much higher than the LRR’s once this is done. The NRF method, therefore, provides a significant potential to improve global-scale discharge predictions. (c) 2009 Elsevier B.V. All rights reserved.

Place, publisher, year, edition, pages
2009. Vol. 368, no 1-4, 237-250 p.
Keyword [en]
Large-scale, Linear reservoir, Routing, Scale independence, Network-response function, Water balance
National Category
Earth and Related Environmental Sciences
Identifiers
URN: urn:nbn:se:uu:diva-120770DOI: 10.1016/j.jhydrol.2009.02.007ISI: 000265424700022OAI: oai:DiVA.org:uu-120770DiVA: diva2:304157
Available from: 2010-03-17 Created: 2010-03-16 Last updated: 2014-02-04
In thesis
1. Large-scale Runoff Generation and Routing: Efficient Parameterisation using High-resolution Topography and Hydrography
Open this publication in new window or tab >>Large-scale Runoff Generation and Routing: Efficient Parameterisation using High-resolution Topography and Hydrography
2010 (English)Doctoral thesis, comprehensive summary (Other academic)
Alternative title[sv]
Storskalig modellering av flödessvarstid ochavrinningsbildning : Effektiv parametrisering baserad på högupplöst topografi och hydrografi
Abstract [en]

Water has always had a controlling influence on the earth’s evolution. Understanding and modelling the large-scale hydrological cycle is important for climate prediction and water-resources studies. In recent years large-scale hydrological models, including the WASMOD-­M evaluated in the thesis, have increasingly become a main assessment tool for global water resources.

The monthly version of WASMOD-M, the starting point of the thesis, revealed restraints imposed by limited hydrological and climate data quality and the need to reduce model-structure uncertainties. The model simulated the global water balance with a small volume error but was less successful in capturing the dynamics. In the last years, global high-quality, high-resolution topographies and hydro­graphies have become available. The main thrust of the thesis was the development of a daily WASMOD-M making use of these data to better capture the global water dynamics and to parameter­ise local non-linear processes into the large-scale model. Scale independency, parsimonious model structure, and computational efficiency were main concerns throughout the model development.

A new scale-independent routing algorithm, named NRF for network-response function, using two aggregated high-resolution hydrographies, HYDRO1k and HydroSHEDS, was developed and tested in three river basins with different climates in China and North America. The algorithm preserves the spatially distributed time-delay information in the form of simple network-response functions for any low-resolution grid cell in a large-scale hydrological model.

A distributed runoff-generation algorithm, named TRG for topography-derived runoff generation, was developed to represent the highly non-linear process at large scales. The algorithm, when inserted into the daily WASMOD-M and tested in same three basins, led to the same or a slightly improved performance compared to a one-layer VIC model, with one parameter less to be calibrated. The TRG algorithm also offered a more realistic spatial pattern for runoff generation.

The thesis identified significant improvements in model performance when 1) local instead of global climate data were used, and 2) when the scale-independent NRF routing algorithm was used instead of a traditional storage-based routing algorithm. In the same time, spatial resolution of climate input and choice of high-resolution hydrography have secondary effects on model performance.

Two high-resolution topographies and hydrographies were used and compared, and new tech­niques were developed to aggregate their information for use at large scales. The advantages and numerical efficiency of feeding high-resolution information into low-resolution global models were highlighted.

Abstract [sv]

Vatten har alltid varit en nyckelfaktor för jordens utveckling. Att förstå och kunna modellera det storska­liga vattenkretsloppet är betydelsefullt såväl för klimatförutsägelser som för studier av vattenresur­ser. På senare år har storskaliga hydrologiska modeller, däribland WASMOD-M som utvärderas i denna avhand­ling, i ökande utsträckning kommit att användas som huvudverktyg för utvärdering av globala vattenresurser.

Den månatliga versionen av WASMOD-M, avhandlingens startpunkt, användes för att påvisa inskränk­ningar som låg i begränsande hydrologi- och klimatdata liksom behovet av att minska model­lens strukturella osäkerheter. Modellen simulerade den globala vattenbalansen med ett mycket litet volymfel (avrinningens långtidsmedelvärde) men var mindre lyckosam att efterlikna dynamiken. Under se­nare tid har globala topografiska och hydrografiska data med hög rumslig upplösning och kvalitet blivit tillgängliga. Avhandlingens huvudsakliga drivkraft var att utveckla WASMOD-M med hjälp av dessa data i syfte att bättre fånga den globala vattendynamiken och för att parametrisera lokala ickelin­jära processer i den storskaliga modellen. Under hela modellutvecklingen har skaloberoende, lågparametrise­rad modellstruktur och numerisk beräkningseffektivitet varit viktiga bivillkor.

En ny skaloberoende svarstidsalgoritm, benämnd NRF (network-response function), som utnyttjar två aggregerade högupplösta hydrografier, HYDRO1k och HydroSHEDS, utvecklades och provades i tre avrinningsområden med olika klimat i Kina och Nordamerika. Algoritmen bevarar den rumsligt fördelade informationen om koncentrationstider i form av enkla responsfunktioner för vattendragsnä­tet för godtyckliga lågupplösta beräkningsrutor in en storskalig hydrologisk modell.

En distribuerad algoritm för avrinningsbildning, benämnd TRG (topography-derived runoff genera­tion), utvecklades för att representera den höggradigt ickelinjära processen i större skalor. Algoritmen användes i den dagliga WASMOD-M och provades i samma tre avrinningsområden som ovan. Modellprestanda blev lika bra eller bättre än en enlagers VIC-modell fast med en parameter mindre att kalibrera. TRG-algoritmen gav ett rimligare rumsligt mönster för avrinningsbildningen.

Avhandlingen har identifierat påtagliga förbättringar i modellprestanda när 1) lokala i stället för globala klimatdata användes och 2) när NRF, den skaloberoende svarstidsalgoritmen användes i stället för en traditionell magasinsbaserad svarstidsalgoritm. Samtidigt har klimatdatas rumsliga upplösning och val av högupplöst hydrografi en andra ordningens inverkan på modellprestanda.

Två högupplösta topografier och hydrografier användes och jämfördes, och nya tekniker utveckla­des för att aggregera deras informationsinnehåll i stora skalor. Fördelarna och den numeriska beräkningsef­fektiviteten av högupplöst information i lågupplösta globala modeller har belysts.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2010. 71 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 725
Keyword
Parameterisation, runoff generation, routing, WASMOD-M, hydrography, data uncertainty, topographic index, scale, river network, response function, HydroSHEDS, HYDRO1k, Dongjiang basin, Parametrisering, avrinningsbildning, flödessvarstid, WASMOD-M, hydrografi, topografiskt index, dataosäkerhet, skala, flödesnät, svarstidssfunktion, HYDRO1k, HydroSHEDS, Dongjiang
National Category
Oceanography, Hydrology, Water Resources
Research subject
Hydrology
Identifiers
urn:nbn:se:uu:diva-121310 (URN)978-91-554-7757-8 (ISBN)
Public defence
2010-04-28, Hambergsalen, Earth sciences centre, Villavägen 16, Uppsala, 10:00 (English)
Opponent
Supervisors
Available from: 2010-04-01 Created: 2010-03-21 Last updated: 2010-07-27Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Authority records BETA

Gong, L

Search in DiVA

By author/editor
Gong, L
By organisation
LUVAL
In the same journal
Journal of Hydrology
Earth and Related Environmental Sciences

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 418 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf