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Troposphere height

Links , pictures, research, information.

troposphere rheemoclineatmosphere temperature layers with,height

In no specific order.

Theory. Height of the troposphere

http://www-das.uwyo.edu/~geerts/cwx/notes/chap01/tropo.html

extract

‘The height of the tropopause depends on the location, notably the latitude, as shown in the figure on the right (which shows annual mean conditions). It also depends on the season (1, 2). Thus, it is about 16 km high over Australia at year-end, and between 12 – 16 km at midyear, being lower at the higher latitudes. At latitudes above 60� , the tropopause is less than 9 -10 km above sea level; the lowest is less than 8 km high, above Antarctica and above Siberia and northern Canada in winter. The highest average tropopause is over the oceanic warm pool of the western equatorial Pacific, about 17.5 km high, and over Southeast Asia, during the summer monsoon, the tropopause occasionally peaks above 18 km. In other words, cold conditions lead to a lower tropopause, obviously because of less convection.

Deep convection (thunderstorms) in the Intertropical Convergence Zone, or over mid-latitude continents in summer, continuously push the tropopause upwards and as such deepen the troposphere. This is because thunderstorms mix the tropospheric air at a moist adiabatic lapse rate. In the upper troposphere, this lapse rate is essentially the same as the dry adiabatic rate of 10K/km. So a deepening by 1 km reduces the tropopause temperature by 10K. Therefore, in areas where (or at times when) the tropopause is exceptionally high, the tropopause temperature is also very low, sometimes below -80� C. Such low temperatures are not found anywhere else in the Earth’s atmosphere, at any level, except in the winter stratosphere over Antarctica.

On the other hand, colder regions have a lower tropopause, obviously because convective overturning is limited there, due to the negative radiation balance at the surface. In fact, convection is very rare in polar regions; most of the tropospheric mixing at middle and high latitudes is forced by frontal systems in which uplift is forced rather than spontaneous (convective). This explains the paradox that tropopause temperatures are lowest where the surface temperatures are highest.

The tropopause height does not gradually drop from low to high latitudes. Rather, it drops rapidly in the area of the subtropical and polar front jets (STJ and PFJ respectively in the Figure on the left), as shown in the Palmen-Newton model of the general circulation (Fig 12.16 or Fig on left). Especially when the jet is strong and the associated front at low levels intense, then the tropopause height drops suddenly across the jet stream. Sometimes the tropopause actually folds down to 500 hPa (5.5 km) and even lower, just behind a well-defined cold front. The subsided stratospheric air within such a tropopause fold (or in the less pronounced tropopause dip) is much warmer than the tropospheric air it replaces, at the same level, and this warm advection aloft (around 300 hPa) largely explains the movement of the frontal low (at the surface) into the cold airmass, a process called occlusion (Section 13.3) (4).

 

 

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Google search.. ‘pictures tropopause height’

https://www.google.com/search?q=picture+tropopause+height&tbm=isch&source=univ&client=firefox-b-d&sa=X&ved=2ahUKEwjlnsDf-bDjAhVDfX0KHcEUAu0QsAR6BAgEEAE&biw=1025&bih=491

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East coast lows (ECL) Australia

In progress.    Current and historical.

6th May 2019.0

Acc g forecasting the development of an ECL off the mid NSW coast on 6th May 2019

A meandering sub tropical jet 200hpa m spawns a surface low within a surface trough off the coast. The AAO/SAM has dropped 1.5 point in the past week and the jets develop tighter bends. The low forms within the peak of the sub tropical jet trough. Here is the forecast

source

http://www.bom.gov.au/australia/charts/viewer/index.shtml?type=windbarb&level=gradient&tz=AEDT&area=GAuR&model=CSCG&chartSubmit=Refresh+View

6th may 2019

AAO link

https://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/aao/aao.shtml

 

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A study of ..Strong high pressure in the Australian region

I will collect information

Archive of MSLP .. Animated .. Time series

http://www.bom.gov.au/cgi-bin/charts/charts.browse.pl

Monthly anomalous MSLP – Australian region

http://www.bom.gov.au/cgi-bin/climate/cmb.cgi?variable=mslp&area=nat&map=anomaly&time=history&steps=1

MSLP ARCHIVES  2002 to current

FTP directory /anon/home/ncc/www/cmb/mslp/anomaly/month/colour/history/nat/ at ftp.bom.gov.au

ftp://ftp.bom.gov.au/anon/home/ncc/www/cmb/mslp/anomaly/month/colour/history/nat/

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Thanks to ‘seabreeze’ for finding some mslp cells over 1040hpa

http://forum.weatherzone.com.au/ubbthreads.php/topics/1492673/58

2015/ 2016

“Pepler. Seasonal Climate Summary for summer 2015-16 . BOM
quote ”
with the mean January sea level pressure 3.8 hPa above average,

the highest January sea level pressure on record, .”

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Here is March..  average mslp

http://www.bom.gov.au/jsp/ncc/climate_averages/mean-sealevel-pressure/index.jsp?period=mar

 

 

 

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Australian weekly weather forecast 2019.

For all states

GO to comments section below for my latest regular updates regarding upcoming weather events.

Click the heading to load if necessary

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After the stalled synoptic pattern of Jan 2019.

https://weathercycles.wordpress.com/2019/01/11/a-stalled-synoptic-pattern-australian-summer-2018_2019/

I thought l would continue posting . The east coast ridging has finally budged since NOV 2018 ( today is  7th feb 2019)The synoptic below shows the first troughing we have had since then. THE AAO was highly positive during this summer period

Fi9th feb 2019 trough

Finally a change in synoptic pattern after 2 months

This pattern is different and probably transitional

FE10th feb 2019 _access11th feb 2019westerly belt replaces the high in the Bight. Signs the westerly belt is becoming more zonal ( wavy). The lack of MSLP gradient is evident on the mainland

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Types of Australian weather. (1895) by Henry Ambrose Hunt

HENRY HUNT has categorised Australian weather regimes

with 40 PICTURES of synoptic patterns. !!!       in 1895

This is an extract from his paper

https://en.wikisource.org/wiki/Types_of_Australian_weather

hunt _ australian weather 1895

LIST OF TYPES OF AUSTRALIAN WEATHER.

I.—Moving Anticyclones, Charts 1, 2, 3.
II.—Monsoonal Rain Storm, Charts 4, 5.
III.—Development of a Cyclonic Storm in Low Latitudes from a Monsoonal Depression, Charts 6, 7.
IV.—Development of a Cyclonic Storm in High Latitudes from a Monsoonal Depression, Charts 8, 9, 10.
V. Conditions favourable for Thunderstorms, Charts 11, 12.
VI.—Cyclonic Thunderstorms, Charts 13, 14.
VII.—Vertical and nearly straight Isobars, Charts 15, 16.
VIII.—Cyclones from North-West, Charts 17, 18, 19.
IX.—Cyclones from North-East, Charts 20, 21, 22.
X.—Tornadoes, Charts 23, 24.
XI.—South-East Gales, Charts 25, 26.
XII.—Development of Cyclones from a Λ Depression, Charts 27, 28.
XIII.—Westerly Winds, Charts 29, 30.
XIV.—Southerly Bursters, Charts 31, 32.
XV.—Black North-Easter, Chart 33.
XVI.—Winds Blowing Against Isobars, Chart 34.
XVII.—Summer Anticyclone, Chart 35.
XVIII.—Winter Anticyclone, Chart 36.
XIX.—Square Headed Λ Depression, Charts 37, 38.
XX.—Advent of an Antarctic Storm, Charts 39, 40.

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This is an excellent read.

The classification of synoptic patterns and the fact it was written in 1895

It is also not difficult for an amateur to read.

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A Stalled synoptic pattern ..Australian summer 2018_2019

stalled synoptic pattern nov_dec_ jan 2018_2019

The synoptic pattern above ……stalled over Australia from about NOV 2018 , all through DEC 2018 and is still current at time of writing. ( Jan 11th 2019)

Persistent ridging on the eastern quadrant of Australia.

Contracted westerly belt .. Which is not unusual for summer

A big dip in tropical isobars right down to 35 s

Cyclone  Penny ( Jan 2019) could not transition south due to ridging in the Tasman blocking

The stalled pattern caused heatwaves as hot air from the interior was directed southward

Very hot temperatures in the interior as no cold fronts or cooler air from the south advected.

Storm lines persisted in the same place as the interior troughing axis remained quasi stationary.

Sydney  were included in many places with severe storms almost daily.

Noting the AAO/SAM had been positive since the first week of November 2018 and was still positive at time of writing 11th jan 2019. That is approximately 63 days so far

6_1_2019 mslp corelated with positive aao

The monsoon trough has not been over the top end of Australia until recently

Thanks to BOM and ACCESS model

http://www.bom.gov.au/australia/charts/viewer/index.shtml

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ENSO..Pacific Ocean basin 2016_2015_2014

PLEASE CLICK ON THE TITLE TO LOAD ALL FURTHER ENTRIES IN THE COMMENTS SECTION BELOW


I was reading and article by Max Gongalez of weatherzone news
about the possibility of an El Nino in 2014
Article here
http://www.weatherzone.com.au/news/increasing-odds-for-el-nino-to-affect-australian-weather-late-2014/27106

EXTRACT

El Nino

(the warm phase) occurs when warmer than average sea surface temperatures (SSTs) prevail over the central and eastern equatorial Pacific Ocean (from late winter to late autumn),

accompanied by high atmospheric pressure over the western Pacific.

This high atmospheric pressure typically leads to lower than average rainfall over Australia during El Nino years.

La Nina

(cool phase) on the other hand, occurs when cooler than average SSTs prevail over the central and eastern equatorial Pacific.

This is accompanied by a low atmospheric pressure over the western Pacific,

thus typically bringing above average rainfall to mainland Australia during La Nina years.
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I thought l would follow this ENSO season by testing this hypothesis/ fact

I will post the global MSLP ( mean sea level pressure) anomalies in the Pacific every month and observe the changing surface MSLP anomaly pattern

The February 2014 MSLP anomalies show low pressure anomalies in both the east and west basin. Although there is a band of high pressure over Australia and the far west basin of the pacific

According to theory .. Low pressure in the east basin is a la Nina indicator

I’m not sure?
I thought low pressure was a symptom of warm SST anomalies..?

mslp global feb 2014

DATA SOURCE
http://www.bom.gov.au/cgi-bin/climate/cmb.cgi?page=top

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I will post MSLP updates each month for 2014 in the comments section below
Please click on the title to load the comments section if it is not there

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Follow ENSO 2014 forum here
http://forum.weatherzone.com.au/ubbthreads.php/topics/1225860/12016

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Australia MSLP Anomalies ..

Click on the title to load the most recent entries in the comment section below

CURRENT SOUTHERN HEMISPHERE MSLP

Click to access IDY65100.pdf

MENU…….

http://www.bom.gov.au/australia/charts/index.shtml?ref=hdr

LINK to MSLP ARCHIVES

http://www.bom.gov.au/australia/charts/archive/index.shtml

Average mean sea level pressure

http://www.bom.gov.au/jsp/ncc/climate_averages/mean-sealevel-pressure/index.jsp

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Here is an example from 2014…… Scroll down to comments for all further additions. Including research papers

January 2014

The eastern quadrant of Australia has had a pronounced High pressure anomaly in Jan 2014

The south west had some generally lower surface pressure anomalies

LEFT.. The actual anomaly.. Right .the mean MSLP

mslp anomlay jan 2014 australia

source
http://www.bom.gov.au/cgi-bin/climate/cmb.cgi?page=map&variable=mslp&vstatus=anomaly&period=month&area=nat

By weathercycles Posted in MSLP
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Global surface pressure (MSLP) anomalies and spatial patterns

PLEASECLICK ON THE HEADING/ TITLE TO LOAD FURTHER ENTRIESFOUND IN THE COMMENT SECTION BELOW

DECEMBER 2013 Monthly anomalous MSLP

dec 2013 mslp global anomaly

source link
http://www.bom.gov.au/cgi-bin/climate/cmb.cgi?page=map&variable=mslp&vstatus=anomaly&period=month&area=global

BOM Main Menu for ATMOSPHERIC LAYERS ANOMALY CHARTS
-sea level pressure(MSLP)
-Geopotential height
-temperature
-winds
-Out going longwave radiation(OLR)

http://www.bom.gov.au/cgi-bin/climate/cmb.cgi?page=top

By weathercycles Posted in MSLP
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SOI…. Southern Oscillation Index

PLEASE CLICK ON THE TITLE TO LOAD ALL FURTHER ENTRIES BELOW

Definition from BOM

http://www.bom.gov.au/climate/current/soihtm1.shtml

 

“The Southern Oscillation Index, or SOI, gives an indication of the development and intensity of El Niño or La Niña events in the Pacific Ocean. The SOI is calculated using the pressure differences between Tahiti and Darwin.

Sustained negative values of the SOI lower than −7 often indicate El Niño episodes. These negative values are usually accompanied by sustained warming of the central and eastern tropical Pacific Ocean, a decrease in the strength of the Pacific Trade Winds, and a reduction in winter and spring rainfall over much of eastern Australia and the Top End.

Sustainted positive values of the SOI greater than +7 are typical of a La Niña episode. They are associated with stronger Pacific trade winds and warmer sea temperatures to the north of Australia. Waters in the central and eastern tropical Pacific Ocean become cooler during this time. Together these give an increased probability that eastern and northern Australia will be wetter than normal.

Technical details

There are a few different methods for calculating the SOI. The method used by the Australian Bureau of Meteorology is the Troup SOI which is the standardised anomaly of the Mean Sea Level Pressure difference between Tahiti and Darwin.”

 

CURRENT SOI.. 30 day moving average

current SOI

source
http://www.bom.gov.au/climate/enso/

Long term time series

http://www.bom.gov.au/climate/influences/timeline/

soi 1876 fom1896soi 1896 to 1916soi 1918 to 1938soi 1940 to 1960soi 1962 to 1982soi 1984 to 2004soi 2004 to 2018