Spatiotemporal Analysis of MODIS Land Surface Temperature With In Situ Meteorological Observation and ERA-Interim Reanalysis: The Option of Model Calibration

The land surface temperature (
Ts
) is an important parameter in land surface and atmosphere studies. A set of synchronously observed “ground-truth” temperature as training data is required for some empirical/semiempirical statistical and neural network methods for retrieving
Ts
from passive microwave (PMW) remote sensing data. To provide information for the choice of the most suitable dataset in
Ts
retrieval of PMW remote sensing, the spatiotemporal comparison between the moderate-resolution imaging spectroradiometer
Ts
(MODIS
Ts
), the meteorologically observed
Ts
(
in situ Ts
), the meteorologically observed near-surface air temperature (
in situ Ta
), and European Center for Medium-Range Weather Forecast reanalysis products, the ERA-Interim
Ts
(ERA
Ts
), in South China for each season's daytime and nighttime is conducted in this paper. Results show that a large discrepancy between the MODIS
Ts
and the
in situ Ts
exists, whereas the discrepancies between the MODIS
Ts
, the
in situ Ta
and the ERA
Ts
are relatively smaller in daytime. For nighttime period, the differences between each dataset are relatively much smaller. Because the MODIS
Ts
is representative at the satellite pixel scale, it has a smaller spatial-scale mismatch with PMW data compared to
in situ
meteorological observation. The MODIS
Ts
is suitable for both the daytime and the nighttime PMW
Ts
model calibration if it is synchronously observed under almost clear-sky condition. By contrast, for the PMW
Ts
model calibration within the daytime period, the synchronously obtained
in situ Ts
is not suitable to be used as training data. If the ground temperature of daytime period derived from PMW is required, but the MODIS
Ts
is unavailable, the
in situ Ta
should be selected as the “ground truth” for the model calibration. However, it should be noticed that the inversion results are the near-surface air temperature rather than the
Ts
. Remarkably, reanalysis products such as the ERA
Ts
presents an alternative choice for both the daytime and the nighttime
Ts
model calibration if there are no MODIS
Ts
products or
in situ
temperature available. After the comparison, an example of PMW
Ts
retrieval for nighttime period was given, showing a promising performance on deriving an applicable PMW
Ts
inversion model based on the selection of an appropriate training dataset.