ERDC Automated Model Calibration Software

Research at the U.S. Army Engineer Research and Development Center (ERDC) has focused on the development of methodologies, or improvement of the efficiency of native algorithms, for the computer-based calibration of hydrologic and environmental models (wherein by efficiency we mean the number of forward model calls necessary for the calibration algorithm to converge on a solution). Our software is written to accommodate a popular model independent and input control file protocol. Two ERDC Technical Reports published in early 2012 demonstrate, by way of example(s), how to use the ERDC implementations of (1) the Levenberg-Marquardt (LM) local search method , and also the Secant LM (SLM) method, an efficiency enhancement to the LM method, and (2) the stochastic global optimization method MLSL, which uses our LM/SLM method for local searches, to calibrate, in a model independent manner, a Gridded Surface Subsurface Hydrologic Analysis (GSSHA) hydrologic model. The two noted technical reports, their related appendix material, and all of the files associated with the examples discussed in each respective report are provided below. Following the initial efforts documented in the two noted technical reports, the LM/SLM and MLSL methods, as well as the stochastic global optimization methods multistart (MS) and trajectory repulsion (TR), which also use the ERDC LM/SLM method implementations for local searches, were directly interfaced with the GSSHA model such that they can be treated as alternate GSSHA run modes. Hence, there are four alternate GSSHA run modes that employ ERDC model calibration software, and their practical use is discussed in sections 18.6.1 - 18.6.4, respectively. Although the ERDC automated model calibration software was written, as previously mentioned, to accommodate a popular model independent protocol, to be consistent with the other alternate GSSHA run modes (such as, Batch, SCE, Monte Carlo), the GSSHA value replacement functionality was utilized instead when the ERDC automated model calibration software was directly interfaced with the GSSHA model to develop the four alternate GSSHA run modes. For clarity, it should be emphasized that one has the flexibility to calibrate a GSSHA hydrologic model either in a model independent manner, as specified in the two noted technical reports, or by using one of the four alternate GSSHA run modes. We recommend that one calibrate a GSSHA hydrologic model using one of the four alternate GSSHA run modes given that the other alternate GSSHA run modes (such as, Batch, SCE, Monte Carlo) also use the GSSHA value replacement functionality. The two previously mentioned technical reports which describe in a clear and practical way how to calibrate, in a model independent manner, a GSSHA hydrologic model are provided, not only for completeness, but also because the documentation is a primary basis to prepare to use any one of the four alternate GSSHA run modes that employ ERDC automated model calibration software. The individual sections (i.e., 18.6.1 – 18.6.4) dedicated to each of the four alternate GSSHA run modes succinctly describe the minor differences, relative to a model independent implementation of the method, and also any additional information that must be supplied to support use of that given alternate run mode to calibrate a GSSHA hydrologic model. Please note that later this calendar year (2012), a published ERDC Technical Note, similar to the two previously mentioned and provided ERDC TRs that document in a clear and practical way how to use the independent ERDC LM/SLM and MLSL implementations to calibrate a GSSHA hydrologic model in a model independent manner, will be provided at this location and its contents will briefly describe and also document, in a clear and practical way, how to use the four alternate GSSHA run modes for practice driven application. Available project resources more often than not limit the time that one can devote to model calibration, and if so, then we recommend that one use the SLM method, possibly also with prior information (please see example 11 in the technical report ERDC-CHL-TR-12-3, below, for an example problem that could serve as a go by). However, if resources do permit a more thorough exploration of model parameter space, then, of the three available stochastic global optimization methods; viz., MS, TR, and MLSL, we recommend that one use MLSL. For further assistance with using the independent ERDC LM, SLM, and MLSL implementations to calibrate a GSSHA hydrologic model in a model independent manner, or with using any one of the four alternate GSSHA run modes, please contact Brian Skahill at Brian.E.Skahill@usace.army.mil or 503-808-3973, or the principal GSSHA hydrologic model developer Charles W. Downer at charles.w.downer@usace.army.mil.

Model Independent Calibration

A Practical Guide to Calibration of a GSSHA Hydrologic Model Using ERDC Automated Model Calibration Software - Efficient Local Search

ERDC-CHL-TR-12-3 A Practical Guide to Calibration of a GSSHA Hydrologic Model Using ERDC Automated Model Calibration Software - Efficient Local Search

ERDC-CHL-TR-12-3 Appendix Material

Example problems for ERDC-CHL-TR-12-3

A Practical Guide to Calibration of a GSSHA Hydrologic Model Using ERDC Automated Model Calibration Software - Effective and Efficient Stochastic Global Optimization

ERDC-CHL-TR-12-2 A Practical Guide to Calibration of a GSSHA Hydrologic Model Using ERDC Automated Model Calibration Software - Effective and Efficient Stochastic Global Optimization

ERDC-CHL-TR-12-2 Appendix Material

Example problems for ERDC-CHL-TR-12-2

Four Alternate GSSHA Run Modes

The four alternate GSSHA run modes are (1) Efficient Local Search, (2) Multistart, (3) Trajectory Repulsion, and (4) Effective and Efficient Stochastic Global Optimization, and as previously mentioned, their practical use is discussed in sections 18.6.1 - 18.6.4. The "Efficient Local Search" and "Effective and Efficient Stochastic Global Optimization" GSSHA run modes refer to the SLM and MLSL methods, respectively.

-GSSHA executable(s)

-test problem, possibly to use as a go by

Please note that later this calendar year (2012), a published ERDC Technical Note, similar to the two previously mentioned and provided ERDC TRs that document in a clear and practical way how to use the independent ERDC LM/SLM and MLSL implementations to calibrate a GSSHA hydrologic model in a model independent manner, will be provided at this location and its contents will briefly describe and also document, in a clear and practical way, how to use the four alternate GSSHA run modes for practice driven application.