LCZO -- Meteorology -- East Peak -- (2002-2016)

OVERVIEW

Description/Abstract

In the hourly file, data in red is not good or not reliable. We have connected two anemometers at different heights on the tower, causing an additional 8 columns for wind vectors and wind speed.

Detailed information about the following major variables is available in Comments/README: Temperature (T), Radiation data, incoming solar radiation (Sin), Relative humidity (RH), Radiation data, photosynthetic active radiation (PAR), Wind speed (U), Wind direction (Udir), Rainfall (P), Horizontal precipitation (HP)

Creator/Author

Scatena, F.N.|Holwerda, F.

CZOs

Luquillo

Contact

Grizelle González, ggonzalez@fs.fed.us, Miguel Leon, Miguel.Leon@unh.edu

Subtitle

East Peak Climate

SUBJECTS

Disciplines

Climatology / Meteorology

Topics

Meteorology

Keywords

Meteorlogy

Variables

Precipitation horizontal|Precipitation|Air temperature_ C|Average relative humidity|Radiation_ incoming PAR|Incoming solar radiation|Mean wind speed|Wind direction|

Variables ODM2

Temperature|Relative humidity|Radiation, incoming|Wind speed|Precipitation|Radiation, incoming PAR|Wind direction

TEMPORAL

Date Start

2002-01-01

Date End

2016-10-24

SPATIAL

Field Areas

East Peak

Location

East Peak

North latitude

18.279714000000002

South latitude

18.279714000000002

West longitude

-65.763838

East longitude

-65.763838

REFERENCE

CZO ID

2619

COMMENTS

Comments

In the hourly file, data in red is not good or not reliable. We have connected two anemometers at different heights on the tower, causing an additional 8 columns for wind vectors and wind speed.

Temperature (T)

The hourly temperature (T) series of the East peak (EP) site were checked for quality by comparing them against the hourly T data of the lower Bisley tower (352 m a.s.l.). This comparison allowed for identifying periods during which T measurements were erroneous due to sensor drift, power failures, or any other reason. Temporary drift (caused by e.g. condensation) or spikes could be fairly well identified, and the data subject to these problems were replaced by NaN’s.

Radiation data, incoming solar radiation (Sin)

The values of incoming solar radiation (Sin) measured at EP have been recorded using multipliers provided by LI-COR. This is not correct, however. Although the pyranometers were manufactured by LI-COR, the sensors were bought from Campbell Scientific (CS). CS adapts the sensors to make them compatible with their data loggers. The adaptation consists of fitting the cable of the sensor with a resistor that is set to give a fixed output (or sensitivity) of 200 W m-2 mV-1 (see CS manual for the LI200X pyranometer). Hence, each sensor has a sensitivity of 200 W m-2 mV-1.

Relative humidity (RH)

The hourly data were first graphed and visually checked for obvious errors such as e.g. spikes (due to e.g. sensor failure or power issues) and the erroneous data were replaced by NaN’s.

Radiation data, photosynthetic active radiation (PAR)

The Photosynthetic Active Radiation (PAR) data were first visually checked for obvious errors (e.g. out of range data) and the erroneous data were replaced by NaN’s. Next, daily PAR totals as measured at the EP station and the SCF station of Whendee Silver were compared with daily totals of Sin observed at the respective stations (Figure 7b). The slopes of the linear regressions of PAR against Sin as calculated from the EP and SCF data (1.77 and 1.89, respectively)

Wind speed (U)

The wind speed (U) data were first visually checked for obvious errors (e.g. out of range data) and the erroneous data were replaced by NaN’s. . U measured at the EP station before July 2004 seems too low (data to the left of the vertical line). The average daily U for this period was 3.2 m s-1, which is considerably lower than the average value of 4.5 m s-1 measured after July 2004. The latter value compares well with the average values of 45 m s-1 reported for by Briscoe (1966), Baynton (1968), and Holwerda (2005).

Wind direction (Udir)

The wind direction (Udir) data were first visually checked for obvious errors (e.g. out of range data) and the erroneous data were replaced by NaN’s. There was fair agreement between the Udir data from the EP and SCF stations. Since measurements were made over complex terrain – where the wind direction is strongly influenced by the local topography  differences between Udir measured at different locations are to be expected. For most of the time, winds were coming from the NE. Considering only days with winds coming from between 0 and 90, the average Udir was 67  9 for EP and 55  12 for SCF. The average measured at EP (67) is close to the average value of 72  10 derived by Holwerda (2005) for the same site (using one year of data from November 2000 until October 2001).

Rainfall (P)

The rainfall (P) data from EP were compared with P measured at the SCF and TCF stations of Whendee Silver. Erroneous data due to e.g. a clogged funnel, or a malfunctioning reed switch or connection were replaced by NaN’s. Reference data from the SCF and TCF stations were not available for the entire period. As such, parts of the EP P series could not be validated against data (Figure 13). The EP P data showed a strong linear relationship with the P data from the SCF and TCF stations (Figure 12). Hence, gaps in the EP P data were filled using linear regression. To account for changes in the calibration coefficients, separate regression relationships were derived for each gap using data from before the gap.

Horizontal precipitation (HP)

The fog gauge data (HP) were screened for obvious errors due to e.g. a malfunctioning reed switch or a clogged funnel. The erroneous were replaced by NaN’s. It is likely that the much higher values of HP were caused by the use of a wrong, or different multiplier in the data logger program. The multiplier that is used normally is 0.1; dividing the ‘too high’ values by 10 yields values of daily HP that are close to those ‘normally’ observed (see Figure 15), suggesting that a multiplier of 1 was used for the data in blue. Hence, the data in blue were corrected by dividing by 10 . From 29 October 2009 onwards, the ‘Wire harp’ fog gauge was replaced by a ‘Modified Juvik’ gauge.