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Signals of climate variability/change in surface water supply of high-mountain watersheds

Case study: Claro River high mountain basin, Los Nevados Natural Park, Andean Central Mountain Range

Chapter 1: Lifting Condensation Level February 2009

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Signals of climate variability/change in surface water supply of high-mountain watersheds

Case study: Claro River high mountain basin, Los Nevados Natural Park, Andean Central Mountain Range

Contract 7147577 – The World Bank Group

Daniel Ruiz Carrascal Línea de Investigación en Hidroclimatología

Grupo de Investigación ‘Gestión del Ambiente para el Bienestar Social - GABiS’ Escuela de Ingeniería de Antioquia

Calle 25Sur No. 42-73, Envigado, Antioquia, Colombia Phone: (57-4) 339-3200; Fax: (57-4) 331 7851; E-mail: pfcarlos@eia.edu.co

Chapter 1: Lifting Condensation Level February 2009

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Escuela de Ingeniería de Antioquia

Executive, academia and research administration

President

Carlos Felipe Londoño Álvarez

Secretary

Olga Lucía Ocampo Toro

Dean of Engineering

Carlos Rodríguez Lalinde

Director of Research Activities

Nathalia Vélez López de Mesa

Director of Research Group ‘GABiS’

Maria del Pilar Arroyave Maya

Director of Environmental Engineering Program

Santiago Jaramillo Jaramillo

Research Team

Principal Investigator

Daniel Ruiz Carrascal

Co-PI

Maria del Pilar Arroyave Maya Adriana María Molina Giraldo Juan Fernando Barros Martínez

Research Assistants

Maria Elena Gutiérrez Lagoueyte Paula Andrea Zapata Jaramillo

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Table of content

1.1 Brief description of circulation patterns 8 1.2 Lifting Condensation Levels estimates 9 1.2.1 1950-inferred and 2050-predicted LCLs 12 1.2.2 Static stability 15 1.3 Instruments 15

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Tables

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1.1 Data gathered at the T/H Data Loggers over the historical period December, 2008-January, 2009 17

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Figures

# Page

1.1 Vertical profiles of mean annual temperature, minimum annual temperature, and annual dew point for the mainstream of the Claro River under historical conditions

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1.2 Spatial distribution of the historical ws-w difference for the selected spatial domain (04°25’N-05°15’N and 75°00’W-76°00’W)

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1.3 Spatial distribution of the estimated Lifting Condensation Level for historical mean and maximum annual temperatures

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1.4 Historical, 1950-inferred and 2050-predicted near-surface lapse rates 12

1.5 Estimated 1950- and 2050-altitudinal changes in the distribution of the mean Lifting Condensation Level

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1.6 Estimated regions of static instability, conditional instability, and static stability in the area of the Claro River’s watershed

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1.7 Temperature/Relative Humidity Data Loggers installed along the defined altitudinal transect 16

1.8 Temperature/Relative Humidity Data Logger installed in the surroundings of the site ‘Salto de la Cueva’ (3,790 m), GPS mark ID 029, and diurnal cycles of ambient temperature and relative humidity for the 5-day period 12/23/2008-12/27/2008

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1.9 Time series of ambient temperatures and relative humidity values collected at the installed T/H sensors during the 5-day period 12/23/2008-12/27/2008

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1.10 Ambient temperatures gathered at the installed T/H sensors and observed over the period from December 23, 2008 through January 30, 2009 (39-day historical period) 18

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Chapter 1

Lifting Condensation Level Thermodynamic and dynamic atmospheric processes play a significant role in the integrity and functioning of Andean high-altitude ecosystems. This chapter describes our analyses of the potential changes in atmospheric stability and lifting condensation levels (LCLs) in the area of the Claro River’s high-altitude basin and its surroundings. The first section provides a brief description of circulation patterns on both regional and local spatial scales. The second section presents some estimates of the LCL for historical and predicted mean annual temperatures and maximum temperatures during the warmest days. A discussion on near-surface environmental lapse rates for 1950-inferred and 2050-predicted temperature conditions is included. Likely upward shifts in LCLs in the spatial domain (04°25’N-05°15’N and 75°00’W-76°00’W) and along the mainstream of the Claro River’s watershed are also estimated. Finally, regions of static instability, conditional instability, and static stability in the area of the Claro River’s watershed are presented for historical climatic conditions. Section 1.3 describes the Temperature/Relative Humidity sensors that have been deployed (up to date) to monitor potential changes in atmospheric stability and the altitude of the LCLs under future climatic conditions. Diurnal cycles of ambient temperatures and relative humidity values observed over recent periods are presented. Finally, various near-surface environmental lapse rates observed in the altitudinal range [3,600 m–4,500 m] are compared with dry and moist (saturated) adiabatic lapse rates.

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1.1. Brief description of circulation patterns1 Regional scale: in Colombia, two large rivers (the Cauca River and the Grande de la Magdalena River) divide the Andes Cordillera into three large mountain ranges: the Occidental (Western), the Central and the Oriental (Eastern) cordilleras. These three mountain branches and their two inter-Andean valleys constitute the so-called Colombian Andean region. The hydro-climatology of this central region is strongly influenced by the behavior of four climate features: the northeasterly trade winds, the easterlies, the Chocó low-level jet-CLLJ (Poveda and Mesa, 2000; Vernekar et al., 2003), and the low-level jet to the east of the Cordillera Oriental (Vernekar et al., 2003). The dynamics and interactions between these climate features and the orography of the Andean mountain ranges produce detailed regional circulation patterns and complex local scale motions. In the Colombian central region, the northeasterly trade winds become current valleys that blow from north to south along the inter-Andean corridors. They are felt at lower altitudes on the flood plains of the Cauca and Magdalena rivers and along the inter-Andean foothills of the high mountain ranges. The easterlies, in turn, are only felt at the summits of the highest Andean peaks (4,800-5,400 m). At these altitudes they have such strong winds that they shape the upper features of local circulation motions. The Chocó jet, on the other hand, occurs at lower levels (from the surface to almost 750 hPa) to the west of the northern Cordillera Occidental. The CLLJ brings moisture from the west Caribbean Sea, the Gulf of Panama and the Eastern Tropical Pacific into Colombia, creating an area of moisture convergence along the Pacific Coast. Finally, the jet to the east of the Cordillera Oriental also occurs at lower levels (from the surface to almost 700 hPa). This jet brings warm moist air from the Tropical Atlantic Ocean into Colombian inlands and creates a zone of moisture convergence over the northern part of the Amazon basin and the eastern foothills of the Cordillera Oriental. The low-level jets exhibit marked variability on inter-annual, intra-annual, and even diurnal timescales. As the intensity of the CLLJ, in particular, is driven by the difference between sea surface temperatures in the Colombian Tropical Pacific Ocean and in El Nino 1+2 region, its strength is dominated by the El Nino–Southern Oscillation (ENSO) cycle. According to Vernekar et al. (2003), the CLLJ tends to be weaker in the warm phase of ENSO (El Niño event) than in the cold phase (La Niña event). As for the diurnal variability, the cores of low-level jets increase in magnitude and vertical extent early in the morning, whereas early in the evening, in contrast, they decrease wind speeds (Vernekar et al., 2003). All these changes in intensity have significant impacts on precipitation patterns throughout the Colombian Central region. Local scale: the west upwind side of the Andean Central Mountain Range (ACMR) exhibits currents of lifting air during the afternoon and movements of masses of sinking air during nighttime. The daytime counter-clockwise cell formed over the west flank of the Central Cordillera brings significant amounts of water vapor from lower to higher levels in the atmosphere, sometimes reaching altitudes of about 7,000 m. The moist convection produced during this uplifting process plays a significant role in the local climate effect of the high ACMR. In the evening, upslope winds are reversed and thus blow from the peaks to the lowlands on the Cauca River’s valley. Such clockwise cell encounters a counter-clockwise cell coming from the opposite side of the valley, creating a zone of deep convection that is associated with the occurrence of heavy storms over the Cauca River’s valley. Some evidence of this atmospheric motion is presented in Section 5.3 of Chapter 5.

1 This section is based on the articles ‘Low-level jets and their effects on the South American summer climate as simulated by the NCEP Eta model’ by Vernekar, Kirtman and Fennessy (2003), and ‘Changing climate and endangered high mountain ecosystems in Colombia’ by Ruiz, Moreno, Gutiérrez, and Zapata (2008).

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Changes in the intensity of the CLLJ and the valley currents, increases in atmospheric temperatures, and abrupt changes in vegetative cover on the West flank of the ACMR seem to be weakening the currents of lifting air. As a consequence, less water vapor is being produced over the Andean cloud forests and less fog could be reaching higher altitudes. Hence, current scenario shows that fog tends to be ‘trapped’ in lower levels of the atmosphere, and only high-level clouds (which have the net effect of increasing surface temperatures) are ‘covering’ high altitude ecosystems. Changes in atmospheric stability and the lifting condensation level are consequently expected in these areas. 1.2. Lifting Condensation Levels estimates Topographic profiles of the Claro River and two important streams (Molinos River and Las Nereidas-Alfombrales Creek, not presented here) were created using the detailed high-resolution digital terrain model of the Claro River’s basin developed by Gutiérrez et al. (2006); see Figure 1.1. Vertical profiles –along the mainstreams– of mean annual temperature, minimum annual temperature, annual dew point, vapor pressure (e), saturation vapor pressure (es), atmospheric pressure (p), relative humidity (RH), mixing ratio (w), saturation mixing ratio (ws), and potential temperature (θ) were created using the spatial distributions discussed by Ruiz et al. (2008). See also Figure 1.2 for the spatial distribution of the ws-w difference for the selected spatial domain (04°25’N-05°15’N and 75°00’W-76°00’W). The abovementioned vertical profiles were defined for historical (see Figure 1.1) and predicted future (2050) climatic conditions. Saturation and actual mixing ratios were estimated through the Clausius-Clapeyron equation for the inferred spatial distributions of mean annual temperature and mean annual dew point, respectively. Analyses of local temperature conditions, conducted for the spatial domain (04°25’N-05°15’N and 75°00’W-76°00’W) and its surroundings, suggest a historical near-surface environmental lapse rate of about -5.65 K/km. This value is consistent with the results of the analyses of regional temperature conditions along the 5°N latitudinal transect (see figures 6.5 and 6.7 in Chapter 6), which suggest historical near-surface environmental lapse rates of about -6.9, -6.0 and -7.6 K/km on the Eastern flank of the Western Cordillera, the Western flank of the ACMR, and the Eastern flank of the ACMR, respectively. As for minimum annual temperatures and annual dew points, previous studies indicate decreases in their values with altitude of about 5.90 and 5.29 K/km, under historical climatic conditions (Chaves and Jaramillo, 1998; Poveda et al., 2001). According to the inferred values, the historical mean annual temperatures along the Claro River’s mainstream range from 19.9°C at lower altitudes (Claro River – Molino River confluence) to 3.2°C at altitudes around 4,450 m (visible headwaters); see Figure 1.1. The historical minimum annual temperatures range from 13.1°C to -2.3°C; the historical mean annual dew points range from 14.6°C to 0.9°C; the historical actual vapor pressures range from 16.6 hPa at lower altitudes to 6.5 hPa in the headwaters; the saturation vapor pressures range from 20.5 hPa to 7.7 hPa under annual average conditions; the mean annual relative humidity exhibits values in the interval [81.5-85.1%]; finally, the estimated ranges of atmospheric pressure, actual mixing ratio, saturation mixing ratio, and potential temperature are [814.6 mb to 602.6 mb], [0.0127 to 0.0067], [0.0156 to 0.0079], and [274.1 K to 239.1 K], respectively. The Lifting Condensation Level (LCL) for historical and predicted climatic conditions was estimated by: (a) comparing the vertical profiles of mixing and saturation mixing ratios and/or comparing the vertical profiles of mean and maximum annual temperatures and mean annual dew point; and (b) through empirical equations, such as the one proposed by Georgakakos and Bras (1984). Figure 1.3 depicts the spatial distributions of the estimated historical LCLs for the selected spatial domain.

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Figure 1.1. Vertical profiles of mean annual temperature (Tmean), minimum annual temperature (Tmin), and annual dew point (Td) for the mainstream of the Claro River under historical conditions. Plots of e, es, p, RH, w, ws, and θ are available in the back-up of these analyses. MTmax and mTmax2 represent the maximum temperatures observed on the warmest and on the coldest days, respectively, at the met station I Las Brisas. MTmin and mTmin2 represent the minimum temperatures observed on the warmest and on the coldest days, respectively, at the same weather station. In general, observed temperatures at Las Brisas are well represented by the linear trends estimating the altitudinal change in Tmean, Tmin, and Td.

Figure 1.2. Spatial distribution of the historical ws-w difference for the selected spatial domain (04°25’N-05°15’N and 75°00’W-76°00’W). The dashed line delineates the high-altitude watershed of the Claro River.

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507 m

5,283 m

754 m

05°15’ N

75°42’ W

04°54’ N

75°19’ W

04°33’ N

75°00’ W

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5,283 m

882 m

5,453 m

375 m

170 m

754 m

1,127 m

373 m

1,909 m

6,145 m

1,669 m

1,162 m1,155 m

Figure 1.3. Spatial distribution of the estimated Lifting Condensation Level (LCL) for historical mean and maximum annual temperatures. Top panel: Digital Elevation Model (DEM) of the El Ruiz–Tolima volcanic massif; red dots denote points of reference over the ground (lowest point along the Cauca River valley –left–, (approx.) summit of El Ruiz ice-capped mountain –center–, and lowest point along the Magdalena River valley –right–). Bottom panel: DEM of the selected domain and altitude of the LCL for historical mean annual temperatures (blue surface) and historical maximum annual temperatures during the warmest days (top crosses). See altitudes of the reference points above sea level and above the ground. Note that this is a schematic diagram; no vertical scale is presented.

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Under historical/current climatic conditions a parcel of air, located on the ground at the lowest point in the Cauca River valley (at an altitude of about 754 m) and with its internal temperature equivalent to the historical mean annual temperature of that site, has to be lifted adiabatically to an altitude of about 1,127 m in order to become saturated with respect to a plane surface of water. Under historical/current climatic conditions, if that parcel has an internal temperature equivalent to the historical maximum temperature during the warmest days of that site, it would require to be lifted adiabatically to an altitude of about 1,909 m in order to become saturated. Similarly, a parcel of air, located on the ground at approximately the summit of El Ruiz ice-capped mountain (at an altitude of about 5,283 m) and with its internal temperature equivalent to the historical mean annual temperature of that site, has to be lifted adiabatically to an altitude of about 5,453 in order to become saturated with respect to a plane surface of water. Under historical/current climatic conditions, if that parcel has an internal temperature equivalent to the historical maximum temperature during the warmest days of that site, it would require to be lifted adiabatically to an altitude of about 6,145 m in order to become saturated. In summary, on the West flank of the ACMR and under historical mean temperature conditions, parcels of air located on the ground at the lowest and highest points in the selected spatial domain have to be lifted adiabatically 373 and 170 m, respectively, in order to get a relative humidity of 100%. Under historical maximum temperature conditions, these parcels of air have to be lifted adiabatically 1,155 and 862 m, respectively, in order to get the same condition. 1.2.1. 1950-inferred and 2050-predicted LCLs Figure 1.4 depicts the estimated lapse rates of historical, 1950-inferred and 2050-predicted temperature conditions. Analyses are supported on section 6.3.3 and figures 6.41 and 6.42 of Chapter 6, and section 2.4 of Chapter 2. According to the observed historical trends in temperature, increases of 10 and 25% in near-surface environmental lapse rates of mean and maximum temperatures, respectively, are inferred to reflect the 1950 prevailing conditions. Also, decreases of 26% and 48% in their historical values are predicted to occur by 2050 under an extreme changing scenario.

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Figure 1.4. Historical, 1950-inferred and 2050-predicted near-surface lapse rates. Minimum temperatures during the warmest days (not shown) and minimum temperatures during the coldest days (not shown) exhibit historical lapse rates of about -4.90 and -5.40 K/km, respectively. Maximum temperatures during the warmest days (MTmax) and maximum temperatures during the coldest days (not shown) exhibit historical lapse rates of about -5.90 and -5.50 K/km, respectively.

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Figure 1.5 depicts the estimated 1950- and 2050-altitudinal changes in the distribution of the LCLs. Since records of dew point are only available at one weather station in the selected spatial domain (station VI Apto Matecana), changes in this climatic variable are not included in these analyses. According to the observed values (see Chapter 6 for details), dew point records gathered at Apto Matecana met station suggest a statistically decreasing trend of about –0.1°C/decade. Therefore, our first approximation could give altitudes of the LCLs below the probable inferred and predicted actual saturation levels. Future analyses (data available) should include the spatial distribution of the statistically significant trends in dew point observed in the selected region. It is suggested that, on the West flank of the ACMR and under 1950-inferred mean temperature conditions, a parcel of air located on the ground at the lowest point used to require to be lifted adiabatically about 288 m in order to get a relative humidity of 100%. Under 1950-inferred maximum temperature conditions, that parcel of air used to require to be lifted adiabatically 978 m in order to get the saturation condition. At the highest point, parcels of air used to be saturated under both 1950-inferred mean and maximum temperature conditions. On the other hand, it is predicted that, by 2050 and under mean temperature conditions, parcels of air located on the ground at the lowest and highest points will require vertical motions of about 597 and 1,088 m, respectively, in order to get saturated with respect to a plane surface of water. Finally, by 2050 and under maximum temperature conditions, those parcels will reach the saturation at altitudes of 1,520 m and 2,541 m above the ground, respectively. Analyses indicate that increasing trends in mean ambient temperatures have probably moved up the LCL over the Cauca River’s inter-Andean valley at a rate of almost 17 m/decade over the past fifty years. Over the peaks of the ACMR, the LCL has likely moved at a rate of almost 34 m/decade over that historical period. Also, analyses of increasing trends in maximum temperatures during the warmest days suggest that the maximum LCL over the Cauca River’s inter-Andean valley has moved up at a rate of 35 m/decade over the past fifty years. Over the mountain peaks, the max LCL has probably shifted its altitude at a rate of 173 m/decade over that historical period. Extrapolations suggest that changes in near-surface mean ambient temperatures could force upward shifts in the Lifting Condensation Level on the Cauca River’s inter-Andean valley and the highest peaks of the ACMR of about 30 m/decade and 109 m/decade, respectively, over the 100-year period 1950-2050 (see timescales in Figure 1.4). Changes in near-surface maximum temperatures during the warmest days could induce upward shifts in the max LCL of about 54 m/decade and 254 m/decade over the same period (see timescales in Figure 1.4). Changes along the mainstream of the Claro River’s basin: under historical climatic conditions a parcel of air, located on the foothills of the ACMR at an altitude of about 1,310 m and with an internal temperature equivalent to the historical mean annual temperature of that site, has to be lifted adiabatically to an altitude of about 1,650 m in order to become saturated with respect to a plane surface of water; see LCL2 (Tmean) in Figure 1.6. Under historical/current climatic conditions, if that parcel has an internal temperature equivalent to the historical maximum temperature during the warmest days of that site, it would require to be lifted adiabatically to an altitude of about 2,421 m in order to become saturated; see LCL2 (Tmax) in Figure 1.6. Analyses suggest that under 1950-inferred mean and maximum temperature conditions, that parcel of air used to reach saturation at altitudes of about 1,539 and 2,162 m, respectively. Under 2050-predicted mean and maximum temperature conditions, that parcel would require reaching altitudes of about 1,959 and 2,946 m, respectively, in order to become saturated with respect to a plane surface of water. Thus, along the mainstream of the Claro River’s watershed, increases in near-surface mean temperatures have probably caused an upward shift in the altitude of the LCL of about 111 m over the past fifty years. The maximum LCL has probably moved up at a rate of 52 m/decade over the same period

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of time. Over the analyzed 100-year period, the mean and maximum LCLs will likely reach 420 and 784 m above the 1950-inferred LCLs.

507 m

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Figure 1.5. Estimated 1950- and 2050-altitudinal changes in the distribution of the mean Lifting Condensation Level. Data are expressed as deviations from the historical mean LCL. Values are plotted over the Digital Elevation Model of the El Ruiz–Tolima volcanic massif for the spatial domain (04°25’N-05°15’N and 75°00’W-76°00’W). Top panel: 1950-altitudinal change; bottom panel: 2050-altitudinal change. See: approximate location of met stations I Las Brisas and XII Cenicafe; Claro River’s high-altitude basin (highlighted streams); points of reference, altitudes above sea level, and change in altitude (∆ LCL).

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1.2.2. Static stability The vertical profile of historical mean annual temperatures was compared with the theoretical paths of dry and moist adiabatic lapse rates, to define the regions of static instability, conditional instability, and static stability in the area of the Claro River’s watershed; see Figure 1.6.

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Figure 1.6. Estimated regions of static instability, conditional instability, and static stability in the area of the Claro River’s watershed. Γd and Γm represent the dry and moist (saturated) adiabatic lapse rates, respectively. LCL1 and LCL2 denote the estimated Lifting Condensation Levels for air parcels located at altitudes of around 700 m (Cauca River Valley) and 1,310 m (foothills of the ACMR or around met station XII), respectively. Shaded and dotted areas represent, respectively, the regions of static instability (environmental lapse rate is greater than Γd) and static stability (environmental lapse rate is smaller than Γd and Γm). The white area between the abovementioned areas depicts the region of conditional (in)stability (environmental lapse rate is between Γd and Γm). In this graph, regions of static instability, conditional instability and static stability are delimited assuming a LCL at an altitude of LCL1(Tmean). Observed temperatures are represented by box-plots: blue for minimum monthly temperatures; red for maximum monthly temperatures. In each box-plot vertical lines from left to right depict the minimum, mean and maximum observed values; boxes represent +1 standard deviations. mTmin2 and MTmin represent the minimum monthly temperatures during the coldest days and the warmest days, respectively; mTmax2 and MTmax represent the maximum monthly temperatures during the coldest and the warmest days, respectively. 1.3. Instruments Up to date, four U23-001 HOBO® Temperature/Relative Humidity Data Loggers (see figures 1.7 and 1.8) have been installed along the previously defined altitudinal transect. These devices are currently collecting data of temperature, relative humidity and dew point on an hourly timescale. Up to date, their available datasets comprise the historical period from December 18, 2008 through January 31, 2009 (see Table 1.1). The T/H data loggers have a temperature range of -40 to 70°C and a relative humidity range of 0 to 100%. The accuracy in temperature readings reaches +0.18°C at an ambient temperature of 25°C; the accuracy in relative humidity reaches +2.5% for values in the range 10 to 90%. Finally, the temporal resolutions are 0.02°C at 25°C and 0.03%, respectively.

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2272886

GPS mark 029

Salto_Cueva

2272887

GPS mark 078

Microcentral

2272888

GPS mark 022

El_Cisne

2272889

GPS mark 037

Nariz_Diablo

SANTA ISABEL NEVADO

CLARO RIVER’S MAINSTREAM

Figure 1.7. Temperature/Relative Humidity Data Loggers installed along the defined altitudinal transect. See Data Logger ID#, linked GPS mark, and location. Up to date, four T/H data loggers have been installed at the following altitudes: 3,790 m; 3,910 m; 4,000 m; and 4,260 m.

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Figure 1.8. Temperature/Relative Humidity Data Logger installed in the surroundings of the site ‘Salto de la Cueva’ (3,790 m), GPS mark ID 029, and diurnal cycles of ambient temperature and relative humidity for the 5-day period 12/23/2008-12/27/2008.

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Table 1.1. Data gathered at the T/H Data Loggers over the historical period December, 2008-January, 2009

T/H Data Logger Site Ambient Temperature [°°°°C] Relative Humidity [%] Dew Point [°°°°C]

Min Max Mean Min Max Mean Min Max Mean

2272886 Mark_029_Salto_Cueva 0.27 18.65 5.46 49.76 100.00 90.57 -3.00 9.83 3.96

2272887 Mark_078_Microcentral -1.36 13.83 4.71 49.34 100.00 93.94 -2.89 13.19 3.71

2272888 Mark_022_El_Cisne -0.48 19.29 5.55 40.89 97.77 80.92 -5.27 8.89 2.38

2272889 Mark_037_Nariz_Diablo -5.45 12.80 2.62 54.95 100.00 95.27 -6.73 9.09 1.89

Figure 1.9 depicts the diurnal cycles of temperature and relative humidity observed at the installed T/H data loggers over the period spanning from December 23, 2008 through December 27, 2008. Figure 1.10 shows the mean values and the hour-to-hour standard deviation of near-surface ambient temperatures gathered at the installed T/H sensors and observed over the period from December 23, 2008 through January 30, 2009.

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/27

/08

06

:00

12

/27

/08

12

:00

12

/27

/08

18

:00

Date and hour [mm/dd/yy hh:mm]

Tem

pera

ture

[C

]

-5

0

5

10

15

20

Tem

pera

ture

[C

]

2272886_Mark_029_Salto_Cueva 2272887_Mark_078_Microcentral

2272888_Mark_022_El_Cisne 2272889_Mark_037_Nariz_Diablo

40

50

60

70

80

90

100

12

/23

/08

00

:00

12

/23

/08

06

:00

12

/23

/08

12

:00

12

/23

/08

18

:00

12

/24

/08

00

:00

12

/24

/08

06

:00

12

/24

/08

12

:00

12

/24

/08

18

:00

12

/25

/08

00

:00

12

/25

/08

06

:00

12

/25

/08

12

:00

12

/25

/08

18

:00

12

/26

/08

00

:00

12

/26

/08

06

:00

12

/26

/08

12

:00

12

/26

/08

18

:00

12

/27

/08

00

:00

12

/27

/08

06

:00

12

/27

/08

12

:00

12

/27

/08

18

:00

Date and hour [mm/dd/yy hh:mm]

Rel

ativ

e H

umid

ity [

%]

40

50

60

70

80

90

100

Rel

ativ

e H

umid

ity [

%]

2272886_Mark_029_Salto_Cueva

2272887_Mark_078_Microcentral

2272888_Mark_022_El_Cisne

2272889_Mark_037_Nariz_Diablo

Figure 1.9. Time series of ambient temperatures and relative humidity values collected at the installed T/H sensors during the 5-day period 12/23/2008-12/27/2008.

18

3600

3700

3800

3900

4000

4100

4200

4300

4400

4500

-4 -2 0 2 4 6 8 10 12 14 16

Temperature [°C]

Alti

tude

[m

]

00:00

06:00

10:0012:00

18:00

029

Γ 06:00 = -8.04 K/km Γ 18:00 = -6.62 K/km

Γd = -9.80 K/km

Γm = -4.90 K/km

078

022

037

Figure 1.10. Ambient temperatures gathered at the installed T/H sensors and observed over the period from December 23, 2008 through January 30, 2009 (39-day historical period). From bottom to top: GPS mark 029 Salto_Cueva (3,790 m); GPS mark 078 Microcentral (3,910 m); GPS mark 022 El_Cisne (4,000 m); and GPS mark 037 Nariz_Diablo (4,260 m). Only five temperatures are presented: 00:00 (black crosses); 06:00 (black squares); 10:00 (black pluses); 12:00 (red triangles); and 18:00 (gray circles). Error bars represent +1.0 standard deviation (error bars for 00:00 and 10:00 temperatures are not displayed). Gray solid lines depict the dry adiabatic lapse rate (Γd = -9.80 K/km); gray dashed lines represent the moist adiabatic lapse rate (Γm), which varies from -4.70 to -5.10 K/km in the altitudinal range [3,600 m – 4,500 m] under historical climatic conditions. In this graph only the saturated adiabatic lapse rate of -4.9 K/km is displayed. At 06:00 and 18:00 the near-surface environmental lapse rates reach -8.04 and -6.62 K/km.