The phrase "a diurnal average" is correct and usable in written English.
It can be used in contexts related to daily measurements or statistics, particularly in fields like meteorology or biology.
Example: "The diurnal average temperature for the region indicates a significant variation between day and night."
Alternatives: "daily average" or "24-hour mean".
The diurnal average air temperature was reduced by up to 2.3 °C.
The analysis of diurnal average trends in number and mass concentrations as well as the high temporal resolution responses of the instruments showed that optical detectors could be very useful to investigate atmospheric aerosol for air quality applications and to individuate and investigate specific pollution events.
To decouple the effect of diurnal temperature variation in the uppermost lunar surface, diurnal averaged brightness temperatures at high frequency channels are used to invert mean diurnal surface and subsurface temperatures based on their bilinear profiles within the regolith layer.
Radiative transfer calculations suggests that during January to May, diurnal averaged aerosol forcing at the surface is −33 Wm2 and at the top of the atmosphere (TOA) above 100 km it is observed to be +9 Wm−2.
Critically, the observation that the DA levels, on average, followed a diurnal pattern with a night-time peak, together with the observation that ultradian locomotor period in female hamsters is longer in the dark vs the daily light phase (Prendergast et al., 2012), is consistent with the LD cycle and/or the circadian pacemaker affecting DUO rhythmicity by altering (extracellular) DA.
This data was then divided into two equally-sized cross-validation datasets, A and B. Average diurnal patterns in the fixed-site UFP data indicates higher concentration counts and higher variability at the city-centre site compared to the urban site.
We have a different pace though, a diurnal quality".
The melt season was characterised by a diurnal cycle.
Most depression has a diurnal rhythm, improving over the course of the day and descending overnight.
The present paper presents a calibration scheme that allowed them to obtain a diurnal correction from the satellite measurements themselves, in particular, by solving for a common diurnal cycle correction using temperatures from all available satellites.
