The authors discuss the uncertainty of computer models with respect to simulation of water such as rain, snow or river flow.
In their summary the team around Georgia Destouni write:
“Climate change is changing more rapidly in the Arctic than in many other places on Earth. To understand and project how the Arctic climate is changing, we use computer models that simulate the climate system. Often, such models are reported to perform better for simulations of temperature than for simulations of water, such as rain, snow or river flow. They are often also reported to be better at large scales than at small scales.
In our research, we have studied how well climate model results agree with meteorological observations, by studying data for 64 different rivers in the Nordic and Arctic regions. Contrary to what we expected, we found that models were about as good in simulating river flow as they were in simulating temperature and clearly better than they were at simulating rain and snow. For simulations of river flow and temperature, models were better at larger scales than smaller scales. Our results mean that it may be possible to use these models for understanding and projecting river flows with a similar reliability as for temperature in this region, at least on large scales.”