Niche Modeling

17
Feb
Lots of Rain

While the US has had record snowfalls, Australia has had its own excesses of precipitation. Below is a 30 day loop of precipitation. The sequence starts with cyclone Olga crossing the coast in the far north east, moving into the Gulf, and tracking south with widespread rain down through the central east and south east.

The rain quickly moves to the east, with heavy rain and storms on the east coast, especially Sydney, but then appears to ‘bounce west’ and collide with a very large trough to bring more widespread rain to inland areas and sweeping to the east again.

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Published by david stockwell in: All Climate
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http://www.moyhu.blogspot.com Nick Stokes

Indeed so. Tropical cyclone rain here in Melbourne. Well, we needed it.
http://www.moyhu.blogspot.com Nick Stokes

Indeed so. Tropical cyclone rain here in Melbourne. Well, we needed it.

http://www.ecoengineers.com/ Steve Short

While we are on this topical subject of lots of rain and particularly rain of high intensity over short durations it is probably worthwhile pointing out that it is now well recognised that short duration rainfall exhibits close to twice the Clausius-Clapeyron (C-C) scaling for maximum rainfall (-> PMF; Probable Maximum Flood) and the 99.9 %ile rainfall whenever the temperature increase is greater than ~5 degrees over an initial temperature of 24 degrees.

This ‘super C-C’ scaling appears to arise from a super scaling of the upwards mass-moisture flux (i.e. for constant RH, SH rising by more than the C-C limit of 7%/degree), dominated by a super C-C scaling of the vertical velocity.

The situation is not so clear with longer durations and this is still an active area of meteorological research. In many cases C-C behaviour is not seen until durations get over about 6 – 12 hours and ARIs get down to 99%.

It is interesting to note that that the state-of-the-art in meteorological research with respect to short duration high intensity rainfall, high percentile rainfalls and PMFs etc is now way ahead of the state-of-the-art in climate modeling……

sherro

Oh to live at Weipa. I remember Innisfail in the mid 60s, when the insides of cafes and so on were full of mold, black all over the walls and ceilings.Any chance the pattern you show can be fitted into a climate model?
http://www.ecoengineers.com/ Steve Short

While we are on this topical subject of lots of rain and particularly rain of high intensity over short durations it is probably worthwhile pointing out that it is now well recognised that short duration rainfall exhibits close to twice the Clausius-Clapeyron (C-C) scaling for maximum rainfall (-> PMF; Probable Maximum Flood) and the 99.9 %ile rainfall whenever the temperature increase is greater than ~5 degrees over an initial temperature of 24 degrees.This 'super C-C' scaling appears to arise from a super scaling of the upwards mass-moisture flux (i.e. for constant RH, SH rising by more than the C-C limit of 7%/degree), dominated by a super C-C scaling of the vertical velocity.The situation is not so clear with longer durations and this is still an active area of meteorological research. In many cases C-C behaviour is not seen until durations get over about 6 – 12 hours and ARIs get down to 99%.It is interesting to note that that the state-of-the-art in meteorological research with respect to short duration high intensity rainfall, high percentile rainfalls and PMFs etc is now way ahead of the state-of-the-art in climate modeling……
Anonymous

Oh to live at Weipa. I remember Innisfail in the mid 60s, when the insides of cafes and so on were full of mold, black all over the walls and ceilings.

Any chance the pattern you show can be fitted into a climate model?
sherro

For Steve Short. Thank you for the observation, which crossed my short post in the mail. If you can readily show deviations from Clausius-Clapeyron classical theoretical physics, should you not close that chapter of the text book and go to another?Abstract from Berg, P., J. O. Haerter, P. Thejll, C. Piani, S. Hagemann, and J. H. Christensen (2009), Seasonal characteristics of the relationship between daily precipitation intensity and surface temperature, J. Geophys. Res., 114, D18102, doi:10.1029/2009JD012008. “Past studies have argued that the intensity of extreme precipitation events should increase exponentially with temperature. This argument is based on the principle that the atmospheric moisture holding capacity increases according to the Clausius-Clapeyron equation and on the expectation that precipitation formation should follow accordingly. We test the latter assumption by investigating to what extent a relation with temperature can be observed intraseasonally in present-day climate. For this purpose, we use observed and simulated daily surface temperature and precipitation over Europe. In winter a general increase in precipitation intensity is indeed observed, while in summer we find a decrease in precipitation intensity with increasing temperature. We interpret these findings by making use of model results where we can distinguish separate precipitation types and investigate the moisture content in the atmosphere. In winter, the Clausius-Clapeyron relationship sets a limit to the increase in the large-scale precipitation with increasing temperature. Conversely, in summer the availability of moisture, and not the atmosphere's capacity to hold this moisture, is the dominant factor at the daily timescale. For convective precipitation, we find a peak like structure which is similar for all subregions, independent of the mean temperature, contrary to large-scale precipitation which has a more monotonic dependence on temperature.”The C-C does not seem to be a fits-all-sizes solution for off the hook suits. Indeed, one can point to devices like cloud chambers in nuclear physices where deviations from C-C are useful for diagnosis of incoming radiation. But those sytems are closely controlled, not like in nature.Time and again I have argued that the abundance of uncharacterised or ill-quantified perturbations in natural climate systems make them sitting ducks for the models to be wrong. In the spectrum from the simplicity of Newton's falling apple to the complexity of Navier-Stokes, they seem to converge towards the N-S end as a study becomes more detailed.I'm still waiting for someone to explain how tropical cyclones can replenish and advance and rain for a thousand km or more over dry land, as has happened fairly often in West Australia.
Anonymous

For Steve Short. Thank you for the observation, which crossed my short post in the mail. If you can readily show deviations from Clausius-Clapeyron classical theoretical physics, should you not close that chapter of the text book and go to another?

Abstract from Berg, P., J. O. Haerter, P. Thejll, C. Piani, S. Hagemann, and J. H. Christensen (2009), Seasonal characteristics of the relationship between daily precipitation intensity and surface temperature, J. Geophys. Res., 114, D18102, doi:10.1029/2009JD012008.
“Past studies have argued that the intensity of extreme precipitation events should increase exponentially with temperature. This argument is based on the principle that the atmospheric moisture holding capacity increases according to the Clausius-Clapeyron equation and on the expectation that precipitation formation should follow accordingly. We test the latter assumption by investigating to what extent a relation with temperature can be observed intraseasonally in present-day climate. For this purpose, we use observed and simulated daily surface temperature and precipitation over Europe. In winter a general increase in precipitation intensity is indeed observed, while in summer we find a decrease in precipitation intensity with increasing temperature. We interpret these findings by making use of model results where we can distinguish separate precipitation types and investigate the moisture content in the atmosphere. In winter, the Clausius-Clapeyron relationship sets a limit to the increase in the large-scale precipitation with increasing temperature. Conversely, in summer the availability of moisture, and not the atmosphere’s capacity to hold this moisture, is the dominant factor at the daily timescale. For convective precipitation, we find a peak like structure which is similar for all subregions, independent of the mean temperature, contrary to large-scale precipitation which has a more monotonic dependence on temperature.”

The C-C does not seem to be a fits-all-sizes solution for off the hook suits. Indeed, one can point to devices like cloud chambers in nuclear physices where deviations from C-C are useful for diagnosis of incoming radiation. But those sytems are closely controlled, not like in nature.

Time and again I have argued that the abundance of uncharacterised or ill-quantified perturbations in natural climate systems make them sitting ducks for the models to be wrong. In the spectrum from the simplicity of Newton’s falling apple to the complexity of Navier-Stokes, they seem to converge towards the N-S end as a study becomes more detailed.

I’m still waiting for someone to explain how tropical cyclones can replenish and advance and rain for a thousand km or more over dry land, as has happened fairly often in West Australia.
sherro

For Steve Short. Thank you for the observation, which crossed my short post in the mail. If you can readily show deviations from Clausius-Clapeyron classical theoretical physics, should you not close that chapter of the text book and go to another?Abstract from Berg, P., J. O. Haerter, P. Thejll, C. Piani, S. Hagemann, and J. H. Christensen (2009), Seasonal characteristics of the relationship between daily precipitation intensity and surface temperature, J. Geophys. Res., 114, D18102, doi:10.1029/2009JD012008. “Past studies have argued that the intensity of extreme precipitation events should increase exponentially with temperature. This argument is based on the principle that the atmospheric moisture holding capacity increases according to the Clausius-Clapeyron equation and on the expectation that precipitation formation should follow accordingly. We test the latter assumption by investigating to what extent a relation with temperature can be observed intraseasonally in present-day climate. For this purpose, we use observed and simulated daily surface temperature and precipitation over Europe. In winter a general increase in precipitation intensity is indeed observed, while in summer we find a decrease in precipitation intensity with increasing temperature. We interpret these findings by making use of model results where we can distinguish separate precipitation types and investigate the moisture content in the atmosphere. In winter, the Clausius-Clapeyron relationship sets a limit to the increase in the large-scale precipitation with increasing temperature. Conversely, in summer the availability of moisture, and not the atmosphere's capacity to hold this moisture, is the dominant factor at the daily timescale. For convective precipitation, we find a peak like structure which is similar for all subregions, independent of the mean temperature, contrary to large-scale precipitation which has a more monotonic dependence on temperature.”The C-C does not seem to be a fits-all-sizes solution for off the hook suits. Indeed, one can point to devices like cloud chambers in nuclear physices where deviations from C-C are useful for diagnosis of incoming radiation. But those sytems are closely controlled, not like in nature.Time and again I have argued that the abundance of uncharacterised or ill-quantified perturbations in natural climate systems make them sitting ducks for the models to be wrong. In the spectrum from the simplicity of Newton's falling apple to the complexity of Navier-Stokes, they seem to converge towards the N-S end as a study becomes more detailed.I'm still waiting for someone to explain how tropical cyclones can replenish and advance and rain for a thousand km or more over dry land, as has happened fairly often in West Australia.

Lots of Rain

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