Usage Policy

Please register here to obtain a login ID and password to access the software tools. In the registration form please tell us how you'll use our code in your research and we would like to include it in our Users and Projects web page. We hope that you find some useful tools for your work here and we look forward to working with you.

The software tools that we are now sharing are the results of the theoretical and computational work that PUORG has done over the years. These tools may be used for non-commercial purposes without restriction. We kindly ask you to acknowledge, cite, and/or reference in the following way:

Suggested Acknowledgment

The software tool "specific name here" provided by Anna Michalak's group (PUORG) at

Suggested Website Citation

Anna Michalak's group (PUORG),

Suggested Journal Citation

Multiplication of Separable Matrices

Yadav, V., A.M. Michalak (2013) “Improving computational efficiency in large linear inverse problems: an example from carbon dioxide flux estimation”, Geoscientific Model Development, 6, 583-590, doi:10.5194/gmd-6-583-2013.

Branch and Bound Algorithms

Yadav, V., K.L. Mueller, A.M. Michalak (2013) “A backward elimination discrete optimization algorithm for model selection in spatio-temporal regression models”, Environmental Modelling & Software, 42 (2013): 88-98,

Geostatistical Downscaling of Multi-Resolution Aquatic Sediment Data

Zhou, Y., and A.M. Michalak, (2009), “Characterizing attribute distributions in water sediments by geostatistical downscaling”, Environmental Science and Technology, 43 (24), 9267-9273, doi:10.1021/es901431y.

Geostatistical Data Fusion for Aerosol Optical Depth

Chatterjee, A., A.M. Michalak, S.R. Paradise, C.E. Miller, A.J. Braverman, R.S. Kahn (2010) “A geostatistical data fusion technique for merging remote sensing and ground-based observations of aerosol optical thickness”, Journal of Geophysical Research – Atmospheres, 115, D20207, doi:10.1029/2009JD013765.

Geostatistical Regression Modeling of Gross Primary Productivity

Yadav, V. K.L. Mueller, D. Dragoni, A.M. Michalak (2010) “A geostatistical synthesis study of factors affecting gross primary productivity in various ecosystems of North America”, Biogeosciences, 7, 2655-2671, doi:10.5194/bg-7-2655-2010.

June North American Inversion Pseudo-Data Study

Gourdji, S., A.I. Hirsch, K. Mueller, A.E. Andrews, and A.M. Michalak (2010) “Regional-scale geostatistical inverse modeling of North American CO2 fluxes: A synthetic data study”, Atmospheric Chemistry and Physics, 10, 6151–6167, 2010, doi:10.5194/acp-10-6151-2010.