Geoscientific Model Development (GMD) is an international scientific journal dedicated to the publication and public discussion of the description, development, and evaluation of numerical models of the Earth system and its components. The following manuscript types can be considered for peer-reviewed publication:
"I believe that the time is ripe for significantly better documentation of programs, and that we can best achieve this by considering programs to be works of literature."
(Donald E. Knuth, Literate Programming, 1984)
"Essentially, all models are wrong, but some are useful."
(George E. P. Box, Robustness in the strategy of scientific model building, 1979)
Ecosystem models provide a powerful tool for simulating ocean biology. Care must be exercised when selecting appropriate equations and parameter values to represent chosen marine ecosystems. Here, we present an efficient plankton model testbed, using simplified physics and coded in the freely available language R. Multiple runs can be undertaken for different ocean sites, permitting thorough evaluation of ecosystem model performance. The testbed also serves as an excellent resource for teaching.
T.R. Anderson, W.C. Gentleman, and A. Yool
The natural abundance of 14C in CO2 dissolved in seawater is often used to evaluate circulation and age in the ocean and in ocean models. We study limitations of using natural 14C to determine the time elapsed since water had contact with the atmosphere. We find that, globally, bulk 14C age is dominated by two equally important components, (1) the time component of circulation and (2) the “preformed 14C-age”. Considering preformed 14C-age is critical for an assessment of circulation in models.
W. Koeve, H. Wagner, P. Kähler, and A. Oschlies
We present a new approach to assess karstic groundwater recharge over Europe and the Mediterranean. Cluster analysis is used to subdivide all karst regions into four typical karst landscapes and to simulate karst recharge with a process-based karst model. We estimate its parameters by a combination of a priori information and observations of soil moisture and evapotranspiration. Independent observations of recharge that present large-scale models significantly under-estimate karstic recharge.
A. Hartmann, T. Gleeson, R. Rosolem, F. Pianosi, Y. Wada, and T. Wagener
We provide improved routines to model the ocean carbonate system, i.e., to compute ocean pH and related variables from dissolved inorganic carbon and total alkalinity. These routines (1) rely on the fastest available algorithm to solve the alkalinity-pH equation, which converges even under extreme conditions; (2) avoid common model approximations that lead to errors of 3% or more in computed variables; and (3) account for large pressure effects on subsurface pCO2, unlike other packages.
J. C. Orr and J.-M. Epitalon
H. Wan, P. J. Rasch, K. Zhang, Y. Qian, H. Yan, and C. Zhao