Data set of climatic factors measured in a low latitude region with warm and humid climate: Solar radiation, cloud cover and sky temperature

The data contained in this article refers to the measurements of climatic factors during an entire year in low latitudes regions with warm and humid climates, in Santa Rosa city from Ecuador. Since the geographical location and the importance of cloudiness in these regions, these measurements have focused on the solar radiation flux, cloud cover and sky temperature. The data obtained have been configured in a weather file for energy calculations, which has been used in the research article “Assessment of the reflectivity and emissivity impact on light metal roofs thermal behaviour, in warm and humid climate” [1].


Specifications
Architecture Specific subject area Building Thermal Behaviour Type of data

Value of the Data
• The data shown in this article contributes to the solar radiation data from the Coast of Ecuador obtained by measurements, which until now has been approximated only by calculations. • The provided information could be used to analyse the different components of the solar radiation in this region: direct and diffuse. In the same way, this information contributes to the determination of radiative cooling capacity of the sky at these latitudes. • The weather file included in this article, which is based on measurements in situ , can be used for different energetic software, and, hence for an accurate thermal analysis of buildings in these regions.

Data Description
The data collection process used in this article had the purpose to established the analysis days conditions of the related research article entitled "Assessment of the reflectivity and emissivity impact on light metal roofs thermal behaviour, in warm and humid climate" [1] , specifically an average day and an extreme day. For this, an annual preliminary evaluation has been carried out based on historical data. From here two months have been chosen with the average climatic conditions sought, October and December. Finally, several weeks of these two months have been measured, where the parameters of the analysis days have been found in the two weeks shown in this article (average day: October 12 and December 7, extreme day: October 10 and December 4).
The climatic parameters measured were collected from a meteorological station throughout the whole year of 2016 [2] . Fig. 1 shows the daily average of the solar irradiation on the horizontal plane throughout the measured year. In addition, this figure shows this parameter obtained by simulations with the use of the Heliodon software [3] , which considers a day with clear sky conditions at this latitude. All measured climatic factors are shown in Supplementary  Table 1.  In addition to these measurements, hourly data of solar irradiation, cloud cover, air temperature and sky temperature were measured in situ during several weeks in October and in December. As mentioned before, these two months contain days with different climate conditions, some of them coincide with the values established for model day with average and extreme conditions. So, one week from every month, which contains these days, are shown below. Fig. 2 shows the data of measured cloud cover, measured global horizontal irradiation, simulated solar irradiation with clear sky conditions, calculated direct normal and diffuse horizontal irradiation based on measurements, and, Fig. 3 contains the measured data of sky temperature and air temperature; in 8 and 7 days respectively of these two months. Since the high cloudiness in this region, the measurements of these two last measured parameters were intended to give an approximation more accurate of the thermal behavior of the sky and its radiative cooling effect. These measured data are also shown in Supplementary Table 2.
Finally, a weather file was configured based on the measurements made in October, which is shown in Supplementary Table 3. The climatic factors shown in this file are: air temperature, dew point, humidity, horizontal infrared radiation, global solar radiation, normal direct solar radiation, diffuse solar radiation, wind velocity, wind direction, cloud cover, rain fall, etc.
Although this weather file is only one week of the year, the days shown have different climatic conditions relevant for the climate of this region, like the average day (October 12th) or the extreme day (October 10th).

Experimental Design, Materials and Methods
Regarding solar radiation, air temperature, humidity, dew point, rainfall, air velocity and wind direction, were collected in intervals of 10 min from a meteorological station with the following characteristics throughout 2016.  These technical specifications are detailed in [4] In regards to the additional measurements: cloud cover and sky temperature, these data were collected in intervals of 2 hours. The graphical changes shown in Figs. 2 and 3 about these parameters are conditioned by the time interval used in measuring it.
The process carried out to measure the cloud cover parameter was visual observation. This process consists in dividing the sky vault into equal quadrants, then, an approximation of percentage of the sky of each quadrant was made. By the last, the four percentages obtained were averaged. The unit used for the information collected was the tenths. This process was supported with a photographic base made simultaneously, see Fig. 4 .
With respect to sky temperature measurements, due to the fact that the sky is not isotropic, its thermal behavior was described through the measurements of its temperature in different points of the sky vault. These measurements were taken from the skyline to the zenith, and they were averaged to obtain one sky temperature, which is the value shown in this article ( Tsky ). The equipment used for these measurements was an infrared thermometer TESTO 830 T4 with the following technical specifications. These technical specifications are detailed in [5] Ethics Statement The work does not involve the subject of humans, animals, or data from social media platforms.