The photolysis module JVAL-14, compatible with the MESSy standard, and the JVal PreProcessor (JVPP)

Abstract. We present version 14 of the photolysis module JVAL. Taking atmospheric conditions as input, JVAL calculates photolysis rate coefficients, i.e. the speed of dissociation of atmospheric molecules in the sunlight. Computational efficiency is obtained through the use of parameters for polynomial curve fitting and lookup tables. Physical changes compared to the previous version include a parameterization of the Lyman-alpha absorption, and an update of the UV/VIS cross sections to the most recent recommended values. JVAL also includes the auxiliary program JVPP (JVal PreProcessor) which pre-calculates these parameters based on the absorption cross sections and quantum yields of the atmospheric molecules. It is possible to use JVAL either as a stand-alone program or as a module inside the Modular Earth Submodel System (MESSy). JVAL is a community model published under the GNU General Public License.