HLY and DLY weather file interactions

[Maya Struzak]

Hello,

I plan to model perennial crop growth with sub-daily weather time steps using .HLY files. I assume variables such as min/max temperature, solar radiation, etc. will be drawn from .DLY files with the same weather station. Could someone confirm or clarify how the WDLST****.DAT and RFDT****.DAT work together?

Thank you!

Maya

[Jaehak]

APEX offers subdaily simulation for only rainfall-runoff-streamflow processes. An hly file provides subdaily rainfall amounts, and we use the Green and Ampt equation to calculate infiltration amounts at time steps. The sum of subdaily infiltration amounts is then passed to daily soil hydraulic calculations such as SMC redistribution, percolation, and evaporation. Subdaily runoff volumes at time steps are passed to reaches for subdaily flood routing, which involves not only the gravity-driven flow but also the diffusive flow of peaks. Daily temperature and other daily weather inputs are used in daily calculations. Once the subdaily rainfall-runoff calculation option is selected, the daily rainfall values in DLY are ignored, while other daily weather values are used in the simulation.