SUMMARY:
The Australian
Bureau of
Meteorology
( BOM )
claims all changes
in Australian
temperatures
since the 1950s
reflect ONLY
the climate !
But the BOM changed
their land surface
weather station's
measuring enclosure
volume, and material,
they don’t maintain
them (a wasp or bee's
nest inside will
generate some heat),
they changed
the measuring
technology, and they
also inappropriately
adjust temperature data
to suit their coming climate
change crisis beliefs.
But never mind all that --
the science is settled.
DETAILS:
For their land surface
weather stations,
Australia’s Bureau
of Meteorology
replaced large
230 liter wooden boxes
thermometer screens,
with small wood
60 liter boxes,
and are now starting
to use small
PVC plastic boxes.
PVC screens
have not been
evaluated
for this purpose.
Their closely-spaced
screen louvers
would warm up quickly,
and their matte-black
interiors would radiate
a higher proportion
of that heat onto the
interior instruments,
than would happen
with white-painted
wooden screens.
But never mind that !
Old, larger boxes
protected the
thermometers
from sudden changes
in air temperature.
Old glass thermometers
are being replaced with
electronic gear that can
record a brief moment
of hot air, that the old,
slow glass thermometers
would miss.
The Australia BOM
ignores equipment changes,
and tells the public
that the science is settled.
But Australia’s
average temperature
has had some amount
of "man made" warming
from:
(1)
Replacement of standard
230-liter Stevenson screens,
with 60-liter screene,
(2)
Introduction of 60-liter
PVC plastic screens,
(3)
Making automatic
weather stations (AWS)
the primary instruments,
from September 1996,
and
(4)
Reducing weather station
maintenance, and cleaning,
to one or fewer site-visits
per year.
In 2017 the BOM
opened seven new
weather stations
in southwestern
NSW .
Their locations
were all in
warm places,
using the small
plastic screens with
matte-black interiors,
that radiate heat onto
the interior instruments
on warm days.
Land surface
weather stations
use thermometers
housed inside
a shelter, called a
Stevenson screen.
Many different
Stevenson screen
types were used
from the 1800s
until 1925 .
In 1925 the 230-liter
wood screens
became the standard,
but some screens
were not replaced
until after WWII.
The standard
230-liter screen is:
-- Semi-gloss
white-painted
( or whitewashed ),
-- A wood box with
double louvered sides
and a ventilated
double-roof, and
-- The base is oriented
so the door faces south.
Horizontally held
maximum
(Tmax) and
minimum
(Tmin)
thermometers,
are located
about 1.2 meters
(4-feet) above
short, unwatered,
natural grass.
Double louvers, and the
ventilated double roof
and floor, ensure
extraneous radiation
( direct, reflected and diffuse )
can't affect measurements.
On September 1, 1972,
all Fahrenheit thermometers
were replaced with Celsius
ones.
In 1973, the small (60-liter)
screen was specified
as the new standard shelter.
Documentation of site
and equipment changes
is not reliable.
Example A:
In 1958, the large
Cahill Expressway opened,
surrounding the Sydney
Observatory weather
station site.
That huge change
was ignored
-- meaning the
nearby Expressway's
warming effect
was included in the
Australia average
temperature.
Example B:
Kent Town Adelaide
warmed when a parking area
was sealed south of the site,
before February 2003,
and a large air-conditioned
indoor sports complex
opened nearby in 2012.
No weather station sites
have stayed the same.