NZ Weather Forum

How long does it have to take before Dunedin gets there own AWS. The current Dunedin Airport AWS, does such a bad job in giving accurate reports for Dunedin (the city), that is should have been changed along time ago. Tonight is a good example, the current obs at 6pm is -1C, Metservice forecasted overnight low 5C

City weather stations are showing temps around 4C. Wouldnt metservice look better aswell if they had a city AWS there??

I think the Musselborough site is closing down to favour a newer one near the Otagon.
...but then it is not an official AWS.
AWS stations tend to favour airports rather than city locations.
Dunedin is unfortunate that it's international airport is somewhat about 10 to 15 miles away from the city, and in a flat location.
Maybe if they drained the upper Otago Harbour and built it up to the possibilty of having an airport close to the city, then a AWS would be installed there,giving accurate weather reports for the city.
.... but I can't see that happening.

JohnGaul
NZTS

Presumably they'd want to put it where the daytime temps. are highest. With just one number (max. temp) it's not exactly easy to give a "representative" temperature for Dunedin. The Musselburgh site has high night minima but its daytime maxima would be a bit lower than many parts further from the water. Overall daily mean there however is higher than in many parts of the urban area (and for many sites in lowland Otago & Cant'y for that matter, because of those night minima). For such complex hilly terrain set around a harbour the picture would only be reasonably informative if numbers from at least 3 different types of site were used. That's not going to happen on any TV channel with the limits imposed on the weather slot!

NZ Thunderstorm Soc wrote:I think the Musselborough site is closing down to favour a newer one near the Otagon.
...but then it is not an official AWS.
AWS stations tend to favour airports rather than city locations.
Dunedin is unfortunate that it's international airport is somewhat about 10 to 15 miles away from the city, and in a flat location.
Maybe if they drained the upper Otago Harbour and built it up to the possibilty of having an airport close to the city, then a AWS would be installed there,giving accurate weather reports for the city.
.... but I can't see that happening.

JohnGaul
NZTS

Musselburgh has been around a long time, and I don't think it will be closing at all. Refer my comments above.

In a straight line its 25km away for the city center, there is probably some AWS that are further away from a towns center, but given the geography of the area, getting Dunedin City Ob's from it is crazy.

03Stormchaser wrote:In a straight line its 25km away for the city center, there is probably some AWS that are further away from a towns center, but given the geography of the area, getting Dunedin City Ob's from it is crazy.

That's true, but it would still be very challenging to find an "average" site for the city - of course what they all want is the warmest one (day temps, that is) they can find.

Christchurch's botanical gardens were the site of the official readings for Christchurch, well for the past 100 or so years, but now that is not so, as official readings for Christcurch are from the AWS at Harewood, the location of the Christchurch International Airport about 7 miles away. 11kms.
Mind you there are no hills between the airport and the botanical gardens but there is a difference in temperatures, especially regarding the influence of the NE seabreeze that covers the majority of Christchurch mostly in the summer months. This Ne not nessessarily reaching the airport to influence the actual readings for Christchurch city.

JohnGaul
NZTS

The bot. Gardens site is still functioning, though. It's about 0.6C warmer than the airport site (overall mean temps - both maxima and minima are higher).

NZ Thunderstorm Soc wrote:Christchurch's botanical gardens were the site of the official readings for Christchurch, well for the past 100 or so years, but now that is not so, as official readings for Christcurch are from the AWS at Harewood

There is no such thing as an official site, merely a choice as to what site is more convenient to use. Metservice own the AWS at the airport so any data they supply will be from there. NIWA own the site in the Gardens. What annoys me is when MetService say in a press release that "its been the warmest day on record in Christchurch" (or whatever) by referring only to the airport record which is only about half the length of the Gardens record.

RWood wrote:The bot. Gardens site is still functioning, though. It's about 0.6C warmer than the airport site (overall mean temps - both maxima and minima are higher).

Urban heat island. All cities around NZ and the world show it in their temperature readings. Its easy to see when driving into and out of Chch in just about any wind condition - the temp on the car thermometer in the city is always around 1-2deg higher than in the surrounding rural area.

Urban heat island. All cities around NZ and the world show it in their temperature readings. Its easy to see when driving into and out of Chch in just about any wind condition - the temp on the car thermometer in the city is always around 1-2deg higher than in the surrounding rural area.

A classic example of that would be the difference in temperature profiles for say, Albert Park or Mechanics Bay in Auckland city, versus Whenuapai.

Don't me started on the Dunedin City temps from the Airport. Though I must admit that any sizeable city has a large temp range within, especially in Winter. Last night I hovered around 2-3°C all night and there was a wicked frost this morning in lower suburbs. In the valley below me it would have easily been 5 or 6°C lower as the cold air sank and stayed overnight.

At 10.30pm tonight there are four websites displaying data on Weather Underground site, 3 in town at 4°C, 4°C & 5°C and the Airport AWS at 0°C

Also, the exposure of the AWS at Dunedin Airport is producing a different range of temperature readings to the original manually operated weather station which closed down about 10 years ago I think. The AWS produces a lot of extremes and is difinitley too warm in summer.

I think Musselborough is a good representation of Dunedin.

There is now a MetService weather station in Dunedin city. I believe this is used for forecasting the Dunedin city temperatures, hence the difference between the forecast min/max temperatures for the city, and the observations from Dunedin airport. The city AWS belongs to the Dunedin City Council.

Details of the station are here... http://www.cityofdunedin.com/city/?page ... stat_about

and observations are here... http://www.cityofdunedin.com/city/?page=weather_station

Weather Watcher wrote:There is now a MetService weather station in Dunedin city. I believe this is used for forecasting the Dunedin city temperatures, hence the difference between the forecast min/max temperatures for the city, and the observations from Dunedin airport. The city AWS belongs to the Dunedin City Council.

Details of the station are here... http://www.cityofdunedin.com/city/?page ... stat_about

and observations are here... http://www.cityofdunedin.com/city/?page=weather_station

Wouldnt it then make sense for Metservice to use these ob's on there webpage then?? Not the Airport readings.

The weather information displayed on this page is read from a weather station situated on the top of the Dunedin Public Art Gallery building in central Dunedin.

Although after you see where the weather station has been situated, maybe dont take those readings either.

TonyT wrote:
Urban heat island. All cities around NZ and the world show it in their temperature readings. Its easy to see when driving into and out of Chch in just about any wind condition - the temp on the car thermometer in the city is always around 1-2deg higher than in the surrounding rural area.

I agree! Try coming down to Brighton in an easterly when it's sunny!

NZstorm wrote:Also, the exposure of the AWS at Dunedin Airport is producing a different range of temperature readings to the original manually operated weather station which closed down about 10 years ago I think. The AWS produces a lot of extremes and is difinitley too warm in summer.

I think Musselborough is a good representation of Dunedin.

Basically agree re Musselburgh. It's a bit on the low side for day temps., a bit high on the night ones. Its overall average is probably reasonable for the populated zone though if you factored in the higher suburbs and not just city and lower altitudes, it would be a little too warm I think.