Sentences with phrase «morning observation time»

Between 1960 and today, the majority of stations switched from a late afternoon to an early morning observation time, resulting a systemic change (and resulting bias) in temperature observations.

Adjustments to U.S. temperatures are dominated by two large non-random systemic biases: changes from afternoon to morning observation times, and the CRS to MMTS transition.

Not exact matches

Unfortunately, most of the volunteer observers who take / took these observations chose to take their once daily observations during daylight, or at best around 10PM, when they were normally awake, so many recording times ended up being either morning or evening.

It has been found that using midnight is quite a bit better than using a morning (e.g. 7AM) or an evening (7PM) observation time.

There has been a systematic tendency over time for American stations to shift from evening to morning observations, resulting in an artificial cooling of temperature data at the stations affected, as noted by Karl et al. 1986.

For a station, when the time of observation is shifted from early evening to early morning, the number of «duplicate» minimum readings in the raw data should increase greatly if there is no other resetting.

Observers shifted over time from evening to morning observation.

Moving the time of observation from afternoon to morning sounds like we are shifting the time we look at the temperature (like one time)-- but that doesn't make sense to me.

For a station that switched observation time from late afternoon to morning, there should be a TOBS adjustment to reduce the Tmax prior to the switch, and a TOBS adjustment to raise the Tmin after the switch.

Dear Zeke «If you change the observations times from afternoons to mornings, as occurred in the U.S., you change from occasionally double counting highs to occasionally double counting lows, resulting in a measurable bias.»

When the time of observation is systematically changed from afternoon to morning in the Climate Reference Network, a clear cooling bias emerges.

Impact of observation time on resulting temperatures (relative to midnight) based on 2004 - 2014 USCRN hourly data.Shaded areas reflect most common morning and afternoon observation times.

2 — As I understand, unless the time of observation is particularly close to the time of Tmax or Tmin (where «double counting» would be a frequent occurrence),, the double counting will only occur for days where there is a marked jump in temperature (so, in the case of morning readings, where the second night is appreciably warmer than the first and so Tmin occurs at the start of the 24 hours).

If you change the observations times from afternoons to mornings, as occurred in the U.S., you change from occasionally double counting highs to occasionally double counting lows, resulting in a measurable bias.

Switching from an afternoon time of observation to a morning time of observation would result in minimum, maximum, and mean temperatures around 0.6 C colder previously measured.