Summary
BCI is an island which was isolated from the surrounding mainland in 1914 following the damming of the Chagres river and the formation of Gatun Lake. The island, rising 137m above Lake Gatun, has an area of 1500 ha which are covered by forest that has remained relatively undisturbed for at least 100 years. BCI forms part of the Barro Colorado Nature Monument (BCNM).
The island receives an average of 2623 mm of rain per year. Day-time temperatures reach an average of 32°C, with night-time lows of approximately 23°C. The meteorological year is divided into two parts: a pronounced dry season (approximately from mid-December to the end of April), and a wet season (May to mid-December). On average, only 285 mm of rain falls during the dry season. Relative humidity, soil moisture, air pressure, solar radiation, evapotranspiration, wind speed and direction all show marked wet/dry season differences. On the other hand, temperature varies relatively little throughout the year.
There are three Physical Monitoring Stations on BCI: The Clearing (‘El Claro’), the Lutz Watershed Weir, the Lutz Tower and the Conrad Weir.
Data are collected using two different methods: electro-mechanical (electronic sensors, data loggers, chart recorders, etc.), and manual (rain gauges, max-min thermometers, sling psychrometers, soil samples, etc.) by a technician. In general, manual measurements have shown themselves to be the most accurate over the long-term. Wherever possible, parameters are measured both manually and electronically. The only exceptions to this rule are solar radiation (electronic only), estimated evapotranspiration (manual only), and gravimetric soil moisture (manual only).
BCI
Location: 9°10’N, 79°51’W
For a summary of the most recent data collected, plus long-term averages report, please click bellow.
Clearing
The Clearing (or ‘El Claro’ as it is know on the island) is a small grass-covered clearing located between the edge of the forest and the foundations of several former laboratory buildings. The station was established in 1972 and was the original meteorological station managed by STRI. An older station (established in 1929 and operated by the Panama Canal Authority) is located near to the shore of Lake Gatun.
The Clearing station records both manual and electronic (tipping bucket) precipitation, manual and electronic temperature and humidity, electronic barometric pressure, as well as manual potential evapotranspiration (EtGage atmometer).
Sensors
| Parameters | Sensor Model | Type | Manual | Methods |
|---|---|---|---|---|
| Barometric Pressure | CS106-PTB110 | Electronic | ⬇️ | |
| Evapotranspiration | ET-Gauge | Manual | ⬇️ | ⬇️ |
| Temperature & RH | Viasala hmp45c (discontinued) Campbell Sci. CS215 | Electronic | ⬇️ | |
| Temperature, daily Max | Novalynx 210-4411 Standard Thermometer | Manual | ⬇️ | |
| Temperature, daily Min | Novalynx 210-4411 Standard Thermometer | Manual | ⬇️ | |
| Temperature, Daily Max/Min | Taylor Model 5458 Min/Max Thermometer | Manual | ⬇️ | |
| Rainfall | Campbell Sci. TB4 tipping bucket | Electronic | ⬇️ | |
| Rainfall | Novalynx rain gauge | Manual | ⬇️ ⬇️ | ⬇️ |
| Relative humidity from wet/dry bulb temperature | BACHARACH Sling Psychrometer | Manual | ⬇️ ⬇️ | ⬇️ |
Electronic Data Download
| Parameters | Frequency | Units | Methods |
|---|---|---|---|
| Air Temperature (max, min, average) | 15 min | Celsius | ⬇️ |
| Barometric Pressure (average) | 15 min | mmHg | ⬇️ |
| Rain (total) | 15 min | mm | ⬇️ |
| Relative Humidity (max, min, average) | 15 min | % | ⬇️ |
Manual Data Download
| Parameters | Frequency | Units | Methods |
|---|---|---|---|
| Rain (daily total) | daily | mm | ⬇️ |
| Temperature, Daily Max/Min | daily | Celsius | ⬇️ |
| Evapotranspiration | daily | cm | ⬇️ |
| Relative Humidity Sling Psychrometer | daily | % | ⬇️ |
Lutz Watershed And Meteorological Tower
The Lutz catchment is probably typical of the many small, steeply-sloped catchments draining away from the center of the island. It is located immediately east of the laboratory clearing. The steeply sloped (20-30°) catchment drains an area of 9.73 ha. The forest covering the catchment was mostly deforested during the construction of the Panama Canal around the turn of the century, but since then it has been allowed to regenerate.
Built in 1972, the Lutz tower was originally 42m in height. In October of 2001 the tower was raised to 48m due to the increase in height of the surrounding forest that happened during the previous 30 years.
The station consists of a vertical meteorological transect through the forest canopy with temperature/humidity sensors at 1, 20, 42 and 48m. . There are solar radiation sensors, an anemometer and an EtGage atmometer on the uppermost level of the tower. Manual measurements of max/min temperature and noon-time relative humidity are taken at the Lutz tower as well.
Gravimetric soil moisture samples are made at ten locations around the Lutz catchment. Soil samples are made at 0-10cm and 30-40cm at each location. Samples are taken every two weeks during the period June to November and weekly from December to May.
The V-notch weir located near the base of the tower measures the run-off from most of the Lutz creek catchment. Data are recorded using both a chart recorder and a pressure-base bubbler. Daily height recordings are made by a technician for calibration purposes.
Sensors
| Parameters | Sensor Model | Type | Manual | Methods |
|---|---|---|---|---|
| Evapotranspiration | ET-Gauge | Manual | ⬇️ | ⬇️ |
| Gravimetric Soil Moisture | n/a | Manual | ⬇️ | |
| Relative humidity from wet/dry bulb temperature | BACHARACH Sling Psychrometer | Manual | ⬇️ ⬇️ | ⬇️ |
| Run-off | ISCO 3230 Bubbler Flow Meter | Electronic | ⬇️ | ⬇️ |
| Solar Radiation | LiCor LI200X pyranometer | Electronic | ⬇️ | ⬇️ |
| Temperature & RH | Viasala hmp45c (discontinued) CAMPBELL SCI. CS700 TIPPING BUCKET | Electronic | ⬇️ ⬇️ | ⬇️ |
| Temperature, daily Max/Min | Novalynx 210-4411 Standard Thermometer | Manual | ⬇️ | |
| Temperature, daily Min/Max | Taylor Model 5458 Min/Max Thermometer | Manual | ⬇️ | |
| Wind speed & direction | Young Wind Monitor AQ | Electronic | ⬇️ | ⬇️ |
| Wind passage | Totalizing Anemometer NovaLynx Model200-2510 | Manual | ⬇️ | ⬇️ |
Electronic Data Download
| Parameters | Frequency | Units | Methods |
|---|---|---|---|
| Air Temperature 1m (max, min, average) | 15 min | Celsius | ⬇️ |
| Air Temperature 20m (max, min, average) | 15 min | Celsius | ⬇️ |
| Air Temperature 42m (max, min, average) | 15 min | Celsius | ⬇️ |
| Air Temperature 48m (max, min, average) | 15 min | Celsius | ⬇️ |
| Relative Humidity 1m (max, min, average) | 15 min | % | ⬇️ |
| Relative Humidity 20m (max, min, average) | 15 min | % | ⬇️ |
| Relative Humidity 42m (max, min, average) | 15 min | % | ⬇️ |
| Relative Humidity 48m (max, min, average) | 15 min | % | ⬇️ |
| Solar Radiation Flux (max, min, average) | 15 min | w/m2 | ⬇️ |
| Wind Direction 45m (vect mean, std. deviation) | 15 min | degrees | ⬇️ |
| Wind Direction 48m (vect mean, std. deviation) | 15 min | degrees | ⬇️ |
| Wind Speed 42m (max, min, mean horiz speed) | 15 min | km/hr | ⬇️ |
| Wind Speed 48m (max, min, mean horiz speed) | 15 min | km/hr | ⬇️ |
| Runoff Lutz Creek (level, flow-rate, discharge) | 5 min | m3 | ⬇️ |
Manual Data Download
| Parameters | Frequency | Units | Methods |
|---|---|---|---|
| Temperature 1m (Daily Max/Min) | daily | Celsius | ⬇️ |
| Temperature 42m (Daily Max/Min) | daily | Celsius | ⬇️ |
| Temperature 48m (Daily Max/Min) | daily | Celsius | ⬇️ |
| Evapotranspiration 42m | daily | cm | ⬇️ |
| Evapotranspiration 48m | daily | cm | ⬇️ |
| Relative Humidity 1m | daily | % | ⬇️ |
| Relative Humidity 20m | daily | % | ⬇️ |
| Relative Humidity 42m | daily | % | ⬇️ |
| Relative Humidity 48m | daily | % | ⬇️ |
| Soil Humidity – Lutz Creek H2O by wet, H2O by dry | 1-2 weeks | % | ⬇️ |
Conrad Weir
The Conrad catchment is a more gently sloped catchment draining much of the central area of the island, including most of the 50-ha plot. The catchment is approximately 40.2 ha in size. Unlike the Lutz catchment, the forest covering the catchment was not cut during the construction of the Panama Canal.
The weir experienced several stages of development between 1993 and 1996 as additional height and wings were added to accommodate all stages of the Conrad stream. The weir consists of a 90 degree ‘V’ set into a two-stage rectangular weir. Data are recorded by a pressure-based bubbler.