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#879316 - 26/08/2010 23:11 Re: Streamflow Observations [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7581
Loc: Adelaide Hills

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#880085 - 31/08/2010 21:49 Re: Streamflow Observations [Re: bigwilly]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7581
Loc: Adelaide Hills
Originally Posted By: bigwilly
Hi Naz,

The BOM's climate section would be the place to go. You can search by location (Woodside - I don't know the region at all so wouldn't know which adjoining stations would suit) for monthly statistics, which should include pan evaporation.

You might have to do a bit of research to determine the relationship between pan evap. and creek/water body/soil evap.

I have what I was looks for, but thanks anyway smile.

Update:

This video:

Video 3, Streamflow Onkaparinga River, 24th August 2010, 3.20 pm

gives an idea of the difference in volume between the 24th and the 25th, and also the rate of flow. At the end of the video I show the riverbank, which was completely submerged the following day.

Total rainfall 10:55 am on the 20th to 11:15 pm tonight was 77.1 mm. 22.7 of that fell between 5:10 pm on the 25th and 8:20 am yesterday.

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#880089 - 31/08/2010 21:56 Re: Streamflow Observations [Re: Surly Bond]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7581
Loc: Adelaide Hills
Originally Posted By: Surly Bond
The Namoi River is flowing high enough for me to see the water from my window. It has been doing it for days. I am reflecting on how rare this sight has become.
Keepit Dam is filling up now, despite the determination of the authorities to empty it out. They have had it steady at 26% for years, despite 2007 and 2008 having rainfall well above average. I was beginning to think that demand would permanently exceed supply. Now Keepit Dam is up to 51%. It will take a little while to use that up.
The smaller upper storage, Split Rock Dam, which filled completely in winter 1998, but was rapidly used up, and has been steady at 2.6% for as long as I can remember, has more than doubled in volume to 5.9%. That could be used in the twinkling of an eye.

The last I heard the local Mount Bold Reservoir was at around 80% capacity. That could be before or after recent rains…whatever it is now, recent weather events could reduce the stress of supply from the River Murray. High flows also tend to flush the system; leading to a sharp drop in salinity before it starts rising again as flows ease.

There are both pros and cons to these significant flows. A highly-vegetated or dense riparian environment (surround a stream) reduces direct runoff to an appreciable degree. This means reduced flood impact on the local environment and industry, particularly agricultural. Less damage means reduced cost impact. European settlement has undoubtedly had environmental and climatic consequences which may have lead to a greater intensity flushing of surface water systems when knowledge of impact of severe weather events is not reflected in policy.

The immediate consequence may be somewhat subtler, however it is noticeable: that is an intensification of the water cycle (flushing) as a result of reduced intermediary processes (vegetation uptake, soil cohesion, etc.). Water is discharged in greater volume and at a greater rate. Though, some inroads have been made on revegetation, etc. in recent years, which is an encouraging sign. Other consequences which are not necessarily connected with climate change include changes in rainfall/evaporation, evapotranspiration and temperature. I think more emphasis should be placed on studying these things (weather and climate variability) and the massive quantities of data waiting to be analysed before we start letting assumptions fly.

It’s enough to say that the science on weather and climate is not settled.

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#880102 - 31/08/2010 23:15 Re: Streamflow Observations [Re: Seira]
Thunderstruck Offline
Lightning man

Registered: 10/05/2001
Posts: 14961
Loc: Seaford Meadows, SA
Looking good there Carl and I bet you it will be RAGING another 2m higher again after this system, it's going to really burst its banks this time.

TS cool

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#880143 - 01/09/2010 09:44 Re: Streamflow Observations [Re: Thunderstruck]
Surly Bond Offline
Weatherzone Addict

Registered: 23/08/2003
Posts: 2137
Loc: Manilla, near Tamworth NSW
Cosmic, I wonder if you have data on how often the Onkaparinga floods over its banks? That would put your observations in context.
I think that over-bank flow in Australia tends to come at about the 50-year flood level, that is, the 2% probability of occurrence in any year.
_________________________
Data are cheap; information is expensive!

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#880303 - 01/09/2010 22:40 Re: Streamflow Observations [Re: Surly Bond]
Seira Offline
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Registered: 27/08/2003
Posts: 7581
Loc: Adelaide Hills
I think the relationship between rainfall and streamflow (and climate) is quite complex along the Onkaparinga River. You may not necessarily get a good correlation between streamflow further downstream (e.g. Verdun/Hahndorf) and rainfall up here. I am aware of some factor which could be playing a role, however my understanding of them is preliminary at this stage; there are many subtle variations and you probably really need to go out in the field and do accurate measurements along the river for calculating variables such as volumetric discharge, etc. Another issue is that you cannot really expect one rain gauge to reflect the flows of a catch of +300 km2, topopgraphic changes or changes in land use, which would effect evapotranspiration. I have attempt a few different methods for sorting out these kind of things, but you really need a whole range of integrated computer software to begin to get a reasonable picture.

The other thing is that, in terms of climate teleconnection, you can sometimes get streamflow-rainfall correlations where a rain gauge several kilometres upstream correlates more reasonably than a closer gauge.

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#880305 - 01/09/2010 23:02 Re: Streamflow Observations [Re: Seira]
Seira Offline
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Registered: 27/08/2003
Posts: 7581
Loc: Adelaide Hills
With the exception of 1992, and the Great Flood of 1956 (the greatest flood on record by an absolute mile), the last breach of the riverbank would have been around 1996.

1996: The same year it snowed in the Adelaide Hills smile.


Edited by -Cosmic- (01/09/2010 23:11)

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#880775 - 03/09/2010 16:31 Re: Streamflow Observations [Re: Seira]
Seira Offline
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Registered: 27/08/2003
Posts: 7581
Loc: Adelaide Hills
I have a little more time than I thought.

The river the will breach the bank if we get enough rain to increase the river height by about 0.5 metres. Though I suspect if 10-20 mm more is on the way, flooding will become major.


Edited by -Cosmic- (03/09/2010 16:32)

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#880842 - 03/09/2010 18:13 Re: Streamflow Observations [Re: Seira]
Seira Offline
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Registered: 27/08/2003
Posts: 7581
Loc: Adelaide Hills
The rain, thunder and lightning started again just after 5 this evening. The river is right up to the bank, and basically flooding in lower-lying areas. It's gradually rising towards minor flooding, however different parts of the river may start flooding at different times. Another metre rise will see the bank breached significantly. The river is 20-30 metres across in places, 2-3 times what it was just 12 hours ago.

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#881099 - 04/09/2010 11:35 Re: Streamflow Observations [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7581
Loc: Adelaide Hills

IDS20364
AUSTRALIAN GOVERNMENT - BUREAU OF METEOROLOGY
SOUTH AUSTRALIA REGIONAL OFFICE

WARNING FOR MINOR FLOODING
FOR THE UPPER ONKAPARINGA RIVER
Issued at 6:00 am on Saturday, 4 September 2010

1. FLOOD WARNING :
Rainfall in the Upper Onkapringa Catchment has ranged from 30-60 mm in the last
24 hours. Further rainfall of 15-30 mm is forecast to fall during Saturday.
River heights are now below minor flood level. Further stream rises exceeding
minor flood level are possible with forecast rainfall.

Motorists are advised to avoid flooded road crossings.
People are advised to keep away from deep and fast-flowing water.

The situation will continue to be monitored and the next warning will be issued
by midday Saturday.

For up to date information on weather forecasts and warnings, please refer to
the Bureau of Meteorology web site: //www.bom.gov.au/weather/sa/


2. RAINFALL AND RIVER HEIGHT OBSERVATIONS :


Latest river height observations for SATURDAY 04/09/2010 :

Onkaparinga R at Charleston 1.55m
Onkaparinga R at Woodside 1.15m
Onkaparinga R at Oakbank 0.71m
Onkaparinga R at Verdun 2.20m
Onkaparinga R at Houlgraves 5.46m
Onkaparinga R at Clarendon 9.98m

Latest details on river heights and rainfall information are available at:
http://www.bom.gov.au/sa/flood/rain_river.shtml


3. WEATHER FORECAST :
Rain periods are expected to ease to showers around sunrise. Showers may be
heavy at times during the day.

The Onkaparinga River at Woodside was 1.7 at ~4.30 yesterday afternoon, but minor flood level is 2 m. It looks like it didn't breach the bank, but it did get very close.

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#882453 - 10/09/2010 15:55 Re: Streamflow Observations [Re: Seira]
Seira Offline
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Registered: 27/08/2003
Posts: 7581
Loc: Adelaide Hills
After experiencing upload problems...

Peak Flow 4, 3rd September 2010, 4,40 pm

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#882457 - 10/09/2010 16:08 Re: Streamflow Observations [Re: Seira]
Seira Offline
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Registered: 27/08/2003
Posts: 7581
Loc: Adelaide Hills

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#882786 - 12/09/2010 21:38 Re: Streamflow Observations [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7581
Loc: Adelaide Hills
The river level in the local Onkaparinga here in the Adelaide Hills appears to have returned to roughly average conditions (in comparison to the 1990s, during which flooding occurred in 1992, 1994 and 1996). It has not flooded significantly in recent days or months, or even years. The latest significant rainfall events over the past 2 weeks (during which we have received 152.6 mm from the 20th of August to the 10th September) have brought flows not seen for 18 years, however I am somewhat sceptical about the significance of the idea that “old patterns” are returning. Relatively speaking I would say we’re tending to more average conditions.

During the early to mid 1990s and leading up to 2000, river flows levels were maintained at sufficient levels that there is a noticeable difference between more recent years and the 1990s. This is not necessarily reflected in weather observations.

I consider the rainfall so far this winter-spring to have broken even with the long-term average; if the long-term average has been exceeded, it’s likely not by much.

Related to streamflow trends, it is quite apparent that evaporation is decreasing by an appreciable quantity annually, while rainfall is gradually increasing. The fact that evaporation, which is a component of evapotranspiration (which is temperature- and radiation-dependent) is decreasing implies to some extent that the moisture already present in the atmosphere is tending (logarithmically) in a similar trend to the near-surface temperature. This can be a somewhat misleading process, as a higher humidity can mean higher near-surface temperatures, which implicates the effects of carbon dioxide as a greenhouse gas.

As the humidity can only increase so much, meaning it has to go somewhere (either be convected to form clouds or be advected due to a pressure gradient), in the absence of significant changes in pressure, on a climatological scale, increased humidity inhibits evapotranspiration (this is explained below). As there is a distinct, appreciable drop in the rate of evaporation (that has lead me to be suspicious that there something else going on with the climate), this implies transpiration is also affected, which means plants are able to retain more moisture.

Given both evaporation and transpiration have a considerable impact on streamflow (and that both occur on any given day, while rainfall does not), this may mean it is not so surprising that flood-like streamflow events become more common in South Australia, and other states. I would however be caution about the suggestion that more flood-like events mean more reliable and consistent rainfall. Many climatological factors appear to point more to a shift in the seasons of up to 2-3 months over a period of 30 years, implying later winter rains. It then possible wet (and cool, for South Australia) conditions could continued well into spring.

Precipitation is likely increasing, regionally, gradually. However globally, this is open to discussion. I do believe the Clausius-Clapeyron relation should not be underestimated in this situation.

As a note of benefit, increasing rainfall and dropping evaporation rates are more evidence in support of climate change, whether natural or man-made, than evidence against it. This is reflected in the change in saturation vapour pressure with change in temperature, and, in many respects, one cannot discount the role of carbon dioxide in these dynamics.

More rainfall means the air has a higher humidity due to the presence of moisture in the atmosphere (mainly as water vapour, but it can also be due to rain). This also means the actual vapour pressure is closer to the saturation vapour pressure (how much moisture the air above the condensation level can hold). If the temperature increases, then the air above the level of condensation can hold more moisture, and the dewpoint will become lower than the actual air temperature. However, carbon dioxide enhances warming by increasing rates of evaporation from the surface and the release of latent heat from the atmosphere (the dewpoint goes up). More moisture in the air enhances the greenhouse effect (warming) due to water vapour. The additional moisture in the air (latent heat) inhibits more and more latent heat from being released in the atmosphere (having a roughly logarithmic effect on temperature increases), and thus the rate of evaporation starts falling on a climatological scale. At the same time, as there is a logarithmic increase in latent heat (driving the saturation vapour pressure up), there is an equilibrium at which the latent heat being released and the moisture-holding capacity of the atmosphere, affected by the water-vapour greenhouse effect, will become constant. This is typically seen at tropical latitudes, but can also occur further north or south. The effect of this equilibrium means the actual temperature will also increase logarithmically in the same sense.

Rainfall increasing means the saturation vapour pressure is being exceeded on a more regular basis; more moisture is being pumped into the atmosphere than it can hold. In theory, in the absence of increasing carbon dioxide in the air, this might not happen, because the released of latent heat would not be as pronounced. That said it may be more understandable why an influence due to carbon dioxide in the atmosphere could lead to trend of slightly increasing rainfall and distinctly reducing evaporation. This still leaves open other possible influences (from the oceans in particular); however, given carbon dioxide is a greenhouse gas, and greenhouse gases are fundamentally responsible for temperature variations, it seems reasonable to keep these things in mind smile.

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#885645 - 27/09/2010 11:58 Re: Streamflow Observations [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7581
Loc: Adelaide Hills
Originally Posted By: -Cosmic-
Related to streamflow trends, it is quite apparent that evaporation is decreasing by an appreciable quantity annually, while rainfall is gradually increasing.

To be more specific, the multi-decadal annual trend in Class A Pan evaporation for this region has been plummeting since roughly 1940. This trend, in some sense, appears to have an inverse sinusoidal relation with several climate phenomena.

On another note, it is taking rather a long time for local streamflow to fall back to pre-winter levels. The photos below were taken on the afternoon of the 10th of September and this morning.

Streamflow Onkaparinga River, approx. 3.50 pm, 10th September 2010
Streamflow Onkaparinga River, approx. 10.50 am, 27th September 2010

Also of interest:



And



10:40 am: Raining briefly for 2-3 minutes, so there is definitely still plenty of moisture in the air passing through the area. We also recorded 0 deg C as an overnight low on the 24th.

About 125 mm for the month to date smile.

Currently drizzle tending to light rain.

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#886145 - 28/09/2010 16:19 Re: Streamflow Observations [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7581
Loc: Adelaide Hills
There is something a little strange about the local weather atm. The humidity is high, temperature around 12 C, and pressure around 1014 hPa, and it has been sporadically drizzling with light showers on-and-off all day, and for the past few days. It seems the only thing missing is atmospheric instability, but there is probably even enough of that around as well. I think what is really needed in these sub-tropical-like conditions (for there is be a deluge) is a bit of heating. The temperature certainly seems to be below some threshold, however it continues to threatened to rain, with spits and spots all over the place! All it’s going to take is a little heat in the right spot from long enough and something may happen!

There also seems to be something sus about the recent streamflow peak. The catchment continues to remains mostly saturated!

Edit: Is it just me or is that 1014 hPa lower than all major Adelaide Mount Lofty Ranges pressure measurements? Even Mount Crawford is about 1019?


Edited by -Cosmic- (28/09/2010 16:26)

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#886500 - 29/09/2010 13:49 Re: Streamflow Observations [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7581
Loc: Adelaide Hills
Re: previous post, rainfall-wise ~ 0.5 mm.

Pictures of Contrast:



Edited by -Cosmic- (29/09/2010 13:56)

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#886535 - 29/09/2010 14:36 Re: Streamflow Observations [Re: Surly Bond]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7581
Loc: Adelaide Hills
Originally Posted By: Surly Bond
Cosmic, I wonder if you have data on how often the Onkaparinga floods over its banks? That would put your observations in context.

In short, rather a lot for the area – somewhere around 60 over a century and a half, when you’re talking about floods in any season.

I could estimate the rainfall for each flood event and from that the streamflow, however I don’t have the computational resources for that kind of analysis, and it would be far more of a long-term endeavour. I would also need streamflow records against which to compare those I estimate to see how reasonable they were, which is not always possible.


Edited by -Cosmic- (29/09/2010 14:36)

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#887521 - 03/10/2010 21:21 Re: Streamflow Observations [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7581
Loc: Adelaide Hills
A rather large pond a good 25-30 m long and 5-wide is still 1-1.5 m deep.



Paddocks are looking very green and lush.

Had a few thundery drops of rain today, but nothing much else. Temperatures in the 20-25 degree range; pressure about 1007 hPa.

Something that might be of interest:

Significant 24-hour rainfall events of greater than or equal to 50 mm to 31/12/2008 are estimated to have occurred on:

17th of December 1992,
7th of July 1993,
31st of October 1997,
21st of February 2000,
3rd of August 2004.

Significant 24-hour rainfall events of greater than or equal to 40 mm to 31/12/2008 (not including those shown above) are estimated to have occurred on:

30th of August 1992,
8th of October 1992,
18th of December 1992,
6th of June 1994,
19th of April 1998,
18th of October 2000,
8th of June 2001,
7th of September 2001,
20th of February 2003,
20th of June 2005,
28th of April 2007,
16th of May 2008,
14th of July 2008.

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#892585 - 21/10/2010 21:37 Re: Streamflow Observations [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7581
Loc: Adelaide Hills
It is possible there is a direct relationship between the mean monthly maximum temperature and the total monthly evaporation which is dependent on the latent heat of vaporisation. In other words if you know the mean monthly maximum temperature, in degrees Celsius, you can calculate the total monthly evaporation, in millimetres. Also of interest is what seems to be, on a monthly timescale, the relationship between evaporation and relative humidity, the square of the latter (mean monthly relative humidity) being dependent on the negative of total evaporation, which is in turn temperature-dependent. In other words, increasing humidity acts to inhibit evaporation (I see this as more of a given). A third potential relationship of interest is that between the square root of total precipitation (in millimetres) and the total monthly dry interval (a count of the length of dry periods, in days, for a given month). You simply total the number of consecutive days without rain on the next rain day, and sum the length of these periods to give the total dry interval. A fourth relationship I find very interest, yet do not completely understand as yet, relates streamflow averaged over a given catchment area (in millimetres per day average depth of water) directly to rainfall for the current and previous months. It also relates an exponential function of the total monthly dry interval (to the power of normalised monthly precipitation) directly to the same streamflow observations (in millimetres per month). This rainfall, dry interval, streamflow relationship is applicable on temporal scales ranging from years (which have higher correlations on average) to days (where high correlations are far more difficult to achieve and justify). In fact, in order to model streamflow (in millimetres per month over a given catchment area) against precipitation on a daily timescale, several timescales of greater than a day are considered, and integrated. The exponential function mentioned earlier is then applied this integral to yield the final streamflow proxies to be regressed against the mathematical transformations of the streamflow observations.

As I am now discovering the dependence of evaporation on relative humidity and temperature, and as, on average, there is far more evaporation than precipitation in Mediterranean climate zones, the next step will be to incorporate evaporation in the streamflow model as a modification of the dry interval function (i.e. replacing the dry interval) to improve the accuracy of this method of streamflow modelling, which, to a limited extent, I have found to be useful throughout the Adelaide Hills, in several cases achieving R Squared values of efficiency of between 0.70 – 0.90.

Climatologically, related to streamflow is the SAM (Southern Annular Mode), which is effectively the end point of the physics described above. The SAM is a function of the zonal pressure anomaly between 40 and 65 degrees south of the equator in the Southern Ocean (although different literature mention different latitudinal ranges, so this may not be a definite reflection of what is meant by the SAM).

Using the psychrometric constant which relates the latent heat of vaporisation to total air pressure, this relationship can be compared to the total monthly evaporation (evaporation is dependent on the latent heat of vaporisation, which in turn is required to calculate the mean maximum air temperature mentioned earlier). By taking the product of the psychrometric ratio (the psychrometric constant without using a parameter for pressure) and total monthly evaporation to the power of a constant and comparing with the original psychrometric constant (pressure-dependent), it seems a high-correlation linear relationship can be established between the two variables (assuming empirical values for evaporation and pressure are used). This relationship can then be roughly plotted on the same line graph to show the significance of the impact of the psychrometric ratio. The end result is a better understanding to role evaporation plays in the determination of how the SAM affects the Adelaide Hills, which it does. Despite the open ocean being a good 200 – 300 kilometres from the Hills, it is still able to have an impact on the region through changes in sea-surface temperatures, which affect evaporation, and total air pressure in turn.

Remembering this is all still theoretical…in conclusion to this rather lengthy critique, sea-surface temperatures in the Southern Ocean, which, above the thermocline, are more affected by incident radiation and wind-driven ocean currents than stratified density differences, respond in a lag, reflected in changes a planetary torque (due to the gravitational pull of the Moon/Sun), of about 2.9 partially-inelastic degrees per tidal cycle (which is somewhat more indirectly related to streamflow) through the motions of the Moon and Sun (affecting tides). The angular momentum of the Earth, which is dependent on latitude, is responsible for generating the fundamental elements of the Coriolis Effect. The Large Rossby Waves in the Southern Ocean, to an extent, reflect the integrated effects of multiple lags (the 2.9-degree elastic torque, which overlaps) over periods spanning weeks to months, which can be clearly and consistently seen when atmospheric and oceanic waves (as a function of the position of the Sun and Moon relative to the Earth) are mapped. The period of these waves, according to the mapping, is about 2.2 waves per month (this does not include effects due to the ionosphere). As these pressure waves approach South Australia, evaporation drops, air temperatures drop, and relative humidity increases. Over the zonal area between 40 and 65 degrees south, sea-surface temperatures respond in a lag to changes in atmospheric pressure due to the differences in density between the ocean and atmosphere (about 1000-fold). As air pressure and evaporation go hand-in-hand (the psychrometric ratio), for the sea-surface temperatures to change appreciably, the rate of evaporation needs to increase appreciably, meaning more sunlight needs to reach the uppermost region of the ocean. Once this starts to happen, the ambient air pressure will increase, and with it the temperature and relative humidity (pressure is temperature- and density-dependent, and relative humidity is temperature-dependent). Once the air is humid enough, advection may occur, where horizontal pressure differences are sufficient to result in a reduction or increase in high-to-low air pressure gradients, wherein partially-inelastic shifts occur to equalise pressure differences. These pressure gradients likely first arose duration the formation of the atmosphere many millions of years ago. While pressure gradients in the atmosphere can change in a matter of hours or days, the motion of near-surface ocean waters (due to atmospheric winds) can take months to years over the same spatial scales. Thus, for example, we cannot expect sea-surface temperatures to respond immediately to changes in air pressure, while the opposite (sea-surface temperatures affecting pressure differences through evaporation and relative humidity) seems far more plausible. So:
  • If incident sunlight increases, sea-surface temperatures increase which increases evaporation.
  • Increasing evaporation increases the air temperature.
  • Increasing evaporation decreases the vapour pressure.
  • Increasing evaporation increases the air pressure and horizontal pressure gradients.
  • If evaporation decreases relative humidity increases.
The mechanism for the passage of a lower-pressure weather system appears to be a change in the pressure gradient. A change in the pressure gradient is brought about by a change in temperature (density changes occur within a small range), and a change in temperature is brought about by a change in the rate of evaporation.

To be continued...


Edited by -Cosmic- (21/10/2010 21:38)

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#893013 - 23/10/2010 21:04 Re: Streamflow Observations [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7581
Loc: Adelaide Hills
In summary:
  • The maximum and minimum daily air temperature could be used to derive the daily evaporation and relative humidity.
  • The daily vapour pressure could be derived from the estimated relative humidity, maximum and minimum air temperatures.
  • The daily mean sea level pressure could be derived from the maximum and minimum air temperatures, daily evaporation and psychrometric ratio as a function of the latent heat of vaporisation.
  • The daily precipitable water (moisture content of the troposphere in millimetres) could be derived from the daily vapour and mean sea level pressures.
  • The daily dewpoint temperature could be derived from the daily vapour pressure.

An example:

Daily maximum air temperature: 23 C
Daily minimum air temperature: 14 C
Daily Evaporation: 2.9 mm.
Daily average relative humidity: 75%.
Daily average vapour pressure: 16 hPa.
Daily average mean sea level pressure: 1017.4 hPa.
Daily average precipitable water: 24.9 mm.
Daily average dewpoint temperature: 14 C.

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