Artigo de peri??dico
Seasonal analysis of the atmosphere during five years by using microwave radiometry over a mid-latitude site
Registro en:
0169-8095
218
10.1016/j.atmosres.2018.11.014
86.559
94.00
Autor
BEDOYA-VELASQUEZ, ANDRES E.
NAVAS-GUZMAN, FRANCISCO
MOREIRA, GREGORI de A.
ROMAN, ROBERTO
CAZORLA, ALBERTO
ORTIZ-AMEZCUA, PABLO
BENAVENT-OLTRA, JOSE A.
ALADOS-ARBOLEDAS, LUCAS
OLMO-REYES, FRANCISCO J.
FOYO-MORENO, INMACULADA
MONTILLA-ROSERO, ELENA
HOYOS, CARLOS D.
GUERRERO-RASCADO, JUAN L.
Resumen
This work focuses on the analysis of the seasonal cycle of temperature and relative humidity (RH) profiles and
integrated water vapor (IWV) obtained from microwave radiometer (MWR) measurements over the mid-latitude
city of Granada, southern Spain. For completeness the study, the maximum atmospheric boundary layer height
(ABLHmax) is also included. To this end, we have firstly characterized the HATPRO-RPG MWR errors using 55 colocated
radiosondes (RS) by means of the mean-bias (bias) profile and the standard deviation (SDbias) profile
classified under all-weather conditions and cloud-free conditions.
This characterization pointed out that temperature from HATPRO-MWR presents a very low bias respects RS
mostly below 2.0 km agl, ranging from positive to negative values under all-weather conditions (from 1.7 to
???0.4 K with SDbias up to 3.0 K). Under cloud-free conditions, the bias was very similar to that found under allweather
conditions (1.8 to ???0.4 K) but with smaller SDbias (up to 1.1 K). The same behavior is also seen in this
lower part (ground to 2.0 km agl) for RH. Under all-weather conditions, the mean RH bias ranged from 3.0 to
???4.0% with SDbias between 10 and 16.3% while under cloud-free conditions the bias ranged from 2.0 to ???0.4%
with SDbias from 0.5 to 13.3%. Above 2.0 km agl, the SDbias error increases considerably up to 4 km agl (up to
???20%), and then decreases slightly above 7.0 km agl (up to???5%). In addition, IWV values from MWR were also
compared with the values obtained from the integration of RS profiles, showing a better linear fit under cloudfree
conditions (R2=0.96) than under all-weather conditions (R2=0.82). The mean bias under cloud-free
conditions was ???0.80 kg/m2 while for all-weather conditions it was ???1.25 kg/m2. Thus, the SDbiasfor all the
statistics (temperature, RH and IWV) of the comparison between MWR and RS presented higher values for allweather
conditions than for cloud-free conditions ones. It points out that the presence of clouds is a key factor to
take into account when MWR products are used.
The second part of this work is devoted to a seasonal variability analysis over five years, leading us to
characterize thermodynamically the troposphere over our site. This city atmosphere presents a clear seasonal
cycle where temperature, ABLHmax and IWV increase from winter to summer and decrease in autumn, meanwhile
RH decreases along the warmer seasons. This city presents cold winters (mean daily maximum temperature:
10.6 ?? 1.1 ??C) and dry/hot summers (mean daily maximum temperature of 28.8 ?? 0.9 ??C and mean
daily maximum of surface RH up to 55.0 ?? 6.0%) at surface (680m asl). Moreover, considering temporal
trends, our study pointed out that only temperature and RH showed a linear increase in winters with a mean-rate
of (0.5 ?? 0.1) ??C/year and (3.4 ?? 1.7) %/year, respectively, from ground to 2.0 km agl, meanwhile IWV presented a linear increase of 1.0 kg??m???2/year in winters, 0.78 kg??m???2/year in summers and a linear decrease in
autumns of ???0.75 kg??m???2/year.