Sentences with phrase «uhi trends»

Here's one simple but very clear picture of UHI trends from Russia (Salehard, Yamal) and here's a Russian scientist from Heartland giving actual figures based on analysing Russian / CRU data rel.

I just used a linear fit to the five year rolling averages and was able to identify UHI trends and other station anomalies.

However, it still requires that the value of the k (i)'s each be such as to provide something so that the UHI trends can be averaged to 0 globally: Still a kind of «conspiracy of nature».

The UHI trends are 0.398 °C and 0.26 °C decade.

For what it's worth, the BEST GST yearly anomaly series is highly (R ^ 2 =.87) correlated (at zero lag) with a world - wide index of century - long records that incorporates capital cities with obvious UHI trends.

-- As I understand Parker's paper, his point was to demonstrate that the global GW trend had not been contaminated by a growing - UHI trend.

# 172 Hans If there is no UHI trend in Tmin or Tmax, but there is a UHI trend in Tmean (or other measures of temperature), then the UHI signal should be detectable in the divergence between the two sets of figures.

He is just saying that the GW signal is not being caused by a UHI trend, because that trend is not big enough.

If the UHI only grows as the logarithm of the population, that could go a long way to explaining why Parker doesn't see any UHI trend.

a) Under this analysis, we see that the difference in calm - day trends and windy - day trends reflects directly whatever is happening with the UHI trend.

Not exact matches

2) Three years ago, I tried to get a handle on whether UHI was responsible for the recent warming trend in most of the temperature datasets by comparing the trends for the UAH / MSU 2LT channel and the Jones et al. surface data for some of the world's «empty places».

How much UHI contamination remains in the global mean temperatures has been tested in papers such as Parker (2005, 2006) which found there was no effective difference in global trends if one segregates the data between windy and calm days.

In calculating no trend between «windy» and «calm» days (with wind data obtained from NCEP / NCAR Reanalysis), Parker (2006), in effect, states that there is no modulation to speak of — in and of itself, that is a remarkable statement, or else there is no UHI to speak of.

This makes sense because UHI effects are stronger on calm days (where there is less mixing with the wider environment), and so if an increasing UHI effect was changing the trend, one would expect stronger trends on calm days and that is not seen.

UHI or buckets or across - satellite calibrations affect estimates of the long term trends.

Hmm... Many adjustments also reduce the trends (such as correcting for UHI and the bucket corrections on the SST).

Lower Tropospheric is as good as any for showing trends, as it removes any UHI effect.

However, you are missing the fundamental point, the gridded data (which attempt to correct for UHI etc.) show a) much smaller trends than the individual station hot spots that jump out of your first figure, and b) clearly reflect the fact that the south east US has in fact cooled.

UHI effects will generally lead to long term trends in an affected station (relative to a rural counterpart), whereas micro-site changes could lead to jumps in the record (of any sign)-- some of which can be very difficult to detect in the data after the fact.

There are quite a few reasons to believe that the surface temperature record — which shows a warming of approximately 0.6 ° -0.8 °C over the last century (depending on precisely how the warming trend is defined)-- is essentially uncontaminated by the effects of urban growth and the Urban Heat Island (UHI) effect.

I am sure that the UHI problem is largely resolved in developed countries, as there are a lot of rural stations which can be used to compensate for the UHI of large towns (there are some residual individual and regional problems, like irrigation in valleys, but that doesn't influence the general trend that much).

[Response: You're missing the point, which is that the UHI is accepted, of course, but the point at issue is whether it affects temperature * trends *, which a constant bias doesn't.

Data trends at climate station with 100 years of record show increasing UHI in areas having experienced large economic growth like at Fort Collins, Billings, Minneapolis.

I'll add that there is a trend in the differences as UHI affected the airport more than the city site (in parklands next to the city centre) for the first 15 years.

Steve Mosher, why should anyone in the industry employ Hockey Team member or likewise for their arctic endeavours, with the esoteric Hockey Stick shattered, sensitivity estimations currently falling apart, temperatures refusing to rise for over a decade and Watts / Evans about to prove that UHI in the US caused exaggerated trends by a factor of 2 or 3?

Although impacts of UHIs on the absolute annual and seasonal temperature are identified, UHI contributions to the long - term trends are less than 10 % of the regional total warming during the period.

Even the most pronounced warming, evident from the cities of Hobart and Melbourne, is within what could be considered natural — though the trends shown here are likely to be artificially exaggerated by the method of measuring temperature since 1996 ** (electronic probes) and the urban heat island (UHI) effect.

I see you wrote 6 paragraphs about your supposed climate «skepticism» arising from the urban heat island effect, but I see not a single word of explanation about why the UHI effect would turn a non-warming trend into a warming trend.

The only way the UHI effect can turn a non-warming trend into a warming trend is if this effect becomes more and more pronounced over time.

Although he doesn't actually come out and say it, Evans suggests that the global warming trend in the surface temperature record is an artifact caused by the urban heat island (UHI) effect:

Or if the natural warming trend was augmented by the UHI, it might not be adjusted for.

I can not believe that people are STILL talking about UHI and siting issues when the oceans tell us these are NOT siginificantly influencing the trend.

Denier is a much better word than skeptic for those that persists in the fallacy that UHI or siting issues are major players in climatic trends.

Among all the interesting details it mentions a few papers that directly discuss efforts to identify and quantify UHI influences on the global temperature trend including this one (PDF), which would be a good one to cite:

If we look at the trends since records began, noting that there are longitudinal problems (changes in locations of weather stations, + UHI effects) and contamination by human analysts (data trickery), the trends seem cyclical in periods of around 60 years.

In the US, the non-urbanized areas have shown little temperature trend, making it difficult to separate the UHI signal from the AGW signal.

Needless, to say, land - based surface temperatures are impacted by other factors, such as upward trends in UHI, ash clouds from volcanic and war activity, persistent contrails and, perhaps, recent geo - engineering efforts.

Overall, UHI effects contribute 24.2 % to regional average warming trends.

It shouldn't be surprising that the UHI effect is not a big source of error in the temperature trend, because a stable temperature bias because of bad siting will not affect the trend.

«We evaluate to what extent the temperature rise in the past 100 years was a trend or a natural fluctuation and analyze 2249 worldwide monthly temperature records from GISS (NASA) with the 100 - year period covering 1906 - 2005 and the two 50 - year periods from 1906 to 1955 and 1956 to 2005... The data document a strong urban heat island eff ect (UHI) and a warming with increasing station elevation... About a quarter of all the records for the 100 - year period show a fall in temperatures... that the observed temperature records are a combination of long - term correlated records with an additional trend, which is caused for instance by anthropogenic CO2, the UHI or other forcings... As a result, the probabilities that the observed temperature series are natural have values roughly between 40 % and 90 %, depending on the stations characteristics and the periods considered.»

Put another way, the pre-1950, the all - natural decadal trend rate of +1.30 °C exceeds the +0.89 °C modern decadal trend attributed to anthropogenic forces (including land - use, the UHI effect, and of course, greenhouse gases).

That said, one must first remove any UHI signal from the trend, and that's a much more complicated thing to do.

There is some other question as to whether «windy - calm» trends mean anything at all with respect to UHI... and if so what that meaning is both alleged to be by (Parker 2006) and actually is, for all values (positive, zero, negative) of «windy - calm» trends.

If you weren't intending to muddy the water over whether Parker is about the existence of UHI, then why did you spend so much time in this article discussing possible experiments, and data sets, and existing papers, and averages, that address whether there is a UHI, and that do NOT address Parker's point about the impact of UHI on trends over time?

c) a) and b) together imply that there is no trend in the UHI *, if there is no difference in the windy - day and calm - day trends.

Even in just the 4 - sentence abstract, sentence 1, the first 7 damn words of the entire article, begins by EXPLICITLY ACCEPTING THE EXISTENCE OF UHI as its premise, and ends by saying «global and regional TRENDS are compared.»

As you know, you and steve Mc and Christy and spencer have all made a similar suggestion that the Trend in TLT should be pretty close to the surface trend, and perhaps that we could bound or estimate the UHI contribution by looking at the difference between those trends.

However, if the rural sites do not show any difference between Ac and Aw, then the difference Parker has recorded is due to UHI which has no trend.

As for UHI data, perhaps one could compare the temperature trends of long - term, mature urban areas like NYC and downtown Chicago with more recent and rapidly developing urban sites like Phoenix / Scottsdale, Orlando FL, Las Vegas NV and Santa Fe NM., or the once rural suburbs of those mature UHI sites.

Using that conclusion, what if on looking at individual station data on an annual basis we find that some years the trend indicates a UHI effect and other years in shows an anti- UHI effect and perhaps other years no effect?