The Use of Visible Geostationary Operational Meteorological Satellite Imagery in Mapping the Water Balance over Puerto Rico for Water Resource Management

A solar insolation satellite remote sensing product for Puerto Rico, the US Virgin Islands (USVI), Dominican Republic, Haiti, Jamaica, and Cuba became available in 2009 through a collaboration between the University of Puerto Rico-Mayagüez Campus and the University of Alabama in Huntsville. Solar insolation data are available at 1 km resolution for Puerto Rico and the USVI and 2 km resolution for the other islands, as derived from 500 m resolution GOES-16 visible imagery. The insolation data demonstrate the powerful utility of satellite-derived fields for water resource applications, specifically the routine production of potential and reference evapotranspiration. This chapter describes the theoretical background and technical approach for estimating components of the daily water and energy balance in Puerto Rico. Useful information can be obtained from the model, which benefits disaster and emergency management, agriculture, human health, ecology, coastal water management, and renewable energy development at the island scale

Estimando evapotranspiración en Puerto Rico

The United Nations Food and Agriculture Organization (FAO) has recommended the Penman-Monteith method as the single method for estimating reference evapotranspiration throughout the world. A disadvantage of the method, however, is its relatively high data requirement. Measurements of wind speed, humidity (or dew point temperature) and radiation tend to be the least available of the required parameters; therefore, the FAO has presented estimation procedures for these parameters. The purpose of this study was to evaluate estimation procedures for climate data to be used in the Penman-Monteith method for estimating long-term daily reference evapotranspiration, and to verify the accuracy of the procedures at four locations in Puerto Rico. Comparison of reference evapotranspiration determined by using the estimated and measured climate data shows reasonably good agreement. The methods presented in this paper are potentially valuable for calculating the long-term average daily reference evapotranspiration at any location in Puerto Rico. An example is provided to illustrate the use of the proposed estimation procedures for climate parameters. This study presents a comparison of reference evapotranspiration calculated by the Penman-Monteith method, with estimates previously made by using the Hargreaves-Samani method, for thirty-four locations in Puerto Rico. In addition, estimated peak evapotranspiration from the Soil Conservation Service (SCS) (now Natural Resources Conservation Service) Irrigation Guide for the Caribbean Area, the SCS Blaney-Criddle method and the Penman-Monteith method were compared for six vegetable crops at three locations in Puerto Rico. The results suggest that some irrigation systems may have been under-designed in terms of flow capacity in Puerto Rico.La Organización de Alimentos y Agricultura de las Naciones Unidas (FAO, por sus siglas en inglés) ha recomendado el método de Penman-Monteith como el único método de calculación que se debería usar para estimar evapotranspiración de referencia a través del mundo. Sin embargo, una desventaja del método es que requiere un número alto de datos. Las medidas de la velocidad del viento, la humedad (o la temperatura de punto de rocío) y la radiación tienden a ser los parámetros requeridos más difíciles de obtener; por ello, la FAO ofrece procedimientos alternos de estimación para estos parámetros. El propósito de este estudio fue evaluar los procedimientos de estimación de los datos del clima requeridos por el método de Penman-Monteith para estimar (a evapotranspiración de referencia promedio diaria a largo plazo y verificar la exactitud de los procedimientos en cuatro zonas de Puerto Rico. Se encontró una alta correlación entre la evapotranspiración de referencia calculada con los datos estimados (FAO) y la calculada con los datos observados del clima. Los métodos presentados son potenciatmente valiosos para calcular la evapotranspiración de referencia promedio diaria en cualquier zona de Puerto Rico. Se provee un ejemplo para ilustrar el uso del procedimiento propuesto para estimar parámetros del clima. Se presenta una comparación de la evapotranspiración de referencia calculada por el método de Penman-Monteith y resultados estimados previamente por el método de Hargreaves-Samani para 34 zonas en Puerto Rico. Además, el estimado máximo de evapotranspiración de la Guía de Riego del Servicio de Conservación de Suelos (SCS) (ahora Servicio de Conservación de Recursos Naturales) para el Área def Caribe, el método de Blaney-Criddfe (SCS) y él método de Penman-Monteith se compararon para seis vegetales en tres localidades en Puerto Rico. Los resultados indican que algunos sistemas de riego no tienen suficiente capacidad para suplir agua en Puerto Rico

Desarrollo de modelos lineales para la determinación del área foliar en habichuela (Phaseolus vulgaris L.) a partir de medidas directas de hojas

Plant leaf area is an important physiological trait, and direct, non-destructive methods for estimating leaf area have been shown to be effective while allowing for repeated plant sampling.The objective of this study was to evaluate direct, non-destructive leaflet measurements as predictors of actual leaflet area (LA), to test previously developed models, and to develop genotype-specific linear models for leaflet area estimation in common bean (Phaseolus vulgaris L.). For development of appropriate regression models for leaflet area estimation, four common bean genotypes were evaluated under greenhouse conditions: BAT 477, 'Morales', SER 16, and SER 21. The greenhouse-derived models were evaluated under field conditions. Previously developed models were tested and found to overestimate or underestimate leaflet area. Leaflet measurements included maximum leaflet width (W) and maximum leaflet length (L) and L X W. The measurements with the highest values for the coefficient of determination (R2) were W or L X W for BAT 477, SER 16, and Morales (0.97, 0.95, and 0.95, respectively), and L X W for SER 21 (R2 = 0.96). The linear models developed were shown to be effective and robust for predicting leaflet area under both greenhouse and field conditions during both vegetative and reproductive stages of plant development.El área foliar es una medida importante de la fisiología de las plantas, y los métodos indirectos y no-destructivos para medir el área foliar han demostrado ser muy eficientes a la vez que permiten la toma de medidas repetidas en el tiempo. El objetivo del presente estudio fue evaluar directamente métodos no destructivos para la estimación del área foliar en habichuelas (Phaseolus vulgaris L.) a partir de la medida de las hojas, probar modelos previos, y desarrollar modelos lineales específicos para cada genotipo. Se evaluaron cuatro genotipos: BAT 477, Morales, SER 16, y SER 21, bajo condiciones de invernadero y de campo. Los modelos desarrollados en invernadero se aplicaron y evaluaron bajo condiciones de campo durante dos años. Los modelos previos reportados por otros autores fueron evaluados, y se encontró que sobre-o sub-estimaban el área foliar. Los modelos desarrollados en este estudio incluyeron el ancho máximo de la hoja (W), y la longitud máxima (L), los que fueron empleados para calcular un tercer factor, L X W. Los modelos con mayores coeficientes de determinación (R2) fueron W or L X W para BAT 477, SER 16 y Morales (0.97, 0.95, y 0.95, respectivamente) y L X W para SER 21 (R2 = 0.96). Los modelos de regresión desarrollados mostraron ser eficientes en la predicción del área foliar bajo condiciones de campo e invernadero, en las fases vegetativas y reproductivas, para cada uno de los genotipos evaluados

Diverse Stellar Haloes in Nearby Milky Way-Mass Disc Galaxies

We have examined the resolved stellar populations at large galactocentric distances along the minor axis (from 10 kpc up to between 40 and 75 kpc), with limited major axis coverage, of six nearby highly-inclined Milky Way-mass disc galaxies using HST data from the GHOSTS survey. We select red giant branch stars to derive stellar halo density profiles. The projected minor axis density profiles can be approximated by power laws with projected slopes of between $-2$ and $-3.7$ and a diversity of stellar halo masses of $1-6\times 10^{9}M_{\odot}$, or $2-14\%$ of the total galaxy stellar masses. The typical intrinsic scatter around a smooth power law fit is $0.05-0.1$ dex owing to substructure. By comparing the minor and major axis profiles, we infer projected axis ratios $c/a$ at $\sim 25$ kpc between $0.4-0.75$. The GHOSTS stellar haloes are diverse, lying between the extremes charted out by the (rather atypical) haloes of the Milky Way and M31. We find a strong correlation between the stellar halo metallicities and the stellar halo masses. We compare our results with cosmological models, finding good agreement between our observations and accretion-only models where the stellar haloes are formed by the disruption of dwarf satellites. In particular, the strong observed correlation between stellar halo metallicity and mass is naturally reproduced. Low-resolution hydrodynamical models have unrealistically high stellar halo masses. Current high-resolution hydrodynamical models appear to predict stellar halo masses somewhat higher than observed but with reasonable metallicities, metallicity gradients and density profiles.Comment: 26 pages, 17 figures. Accepted for publication in MNRA

Percolación y lixiviación de nitrógeno durante el establecimiento y mantenimiento de gramas de césped en el sur de Puerto Rico.

Inadequate nutrient and irrigation management of turfgrass may result in nitrate (N03) losses by leaching, and may contribute to elevated N03-N concentrations in groundwater. A field study was conducted to evaluate the effect of three irrigation levels on the N03-N concentration in soil solution and the mass of total N03-N lost by leaching for three grasses: Bermuda [Cynodon dactylon (L.) Pers.], Centipede [Eremochloa ophiuroides (Munro.) Hack], and Zoysia manila [Zoysia matrella (L.) Merr.]. The study was conducted at Juana Díaz, Puerto Rico, on a San Antón soil (fine-clayey, montmorillonitic, isohyperthermic Cumulic Haplustolls) from June 2001 until September 2002. Soil water N03-N concentrations below the root zone were obtained from water samples collected from suction lysimeters. The levels of irrigation applied were 75,100 and 125% of the daily evapotranspiration (ET), calculated by using the pan evaporation method. Grass was fertilized with 165 kg N/ha/yr, split into four applications. The Bermuda grass exhibited the highest rate of horizontal growth (cover), reaching maximum cover in 45 days, whereas the others reached maximum cover in 120 days. Bermuda grass was the most efficient in reducing the loss of N03-N, with a mean annual soil water concentration below the root zone of 3.24 mg/L, whereas Zoysia and Centipede grasses were less efficient with mean annual soil water concentrations below the root zone of 17.4 and 17.8 mg/L, respectively. The soil solution concentration of N03-N did not change significantly for the Bermuda grass with increases in the level of irrigation. However, lower mean annual N03-N concentrations were observed for the Centipede and Zoysia grasses at the irrigation levels of 100% and 75% ET, with mean values of 14.0 and 11.1 mg/L, respectively. The Bermuda grass had an acceptable color index at the 100% ET, and resulted in decreased N03-N concentrations and mass losses. On the other hand, Zoysia and Centipede grasses presented a commercially acceptable color index and minimal N03-N leaching at the 75% ET irrigation level. The results from this study provide valuable information related to water and nutrient management for the turfgrass industry in southern Puerto Rico.Un manejo inadecuado de gramas de césped puede incrementar las concentraciones de nitrato (N03-) en el agua del suelo y causar mayor lixiviación de nitrógeno (N) a aguas subterráneas. Se realizó un experimento de campo en Juana Díaz, Puerto Rico, de junio 2001 a septiembre 2002. Se evaluó el efecto de tres niveles de riego en la calidad de la grama, la extracción de N, concentración de N03-N en la solución del suelo y la pérdida de N03-N usando tres gramas de césped: Bermuda [Cynodon dactylon (L.) Pers.], Ciempiés [Eremochloa ophiuroides (Munro) Hack.] y Zoysia manila [Zoysia matrella (L.) Merr.]. El suelo pertenece a la serie San Antón (fino arcilloso, montmorilonítico, isohipertérmico Cumulic Haplustolls). Las concentraciones de nitrato por debajo de la zona radicular se obtuvieron de lisímetros. Los niveles de riego aplicado fueron 75,100 y 125% de la evapotranspiración diaria, calculada por medio del método del tanque de evaporación. Las gramas se fertilizaron con un total de 165 kg N/ha, dividido en cuatro aplicaciones al año. La grama Bermuda obtuvo la máxima cobertura en 45 días, mientras que las demás gramas obtuvieron máxima cobertura en 120 días. La grama Bermuda fue la más eficiente en reducir la concentración de N03-N, con una concentración promedio anual de 3.24 mg/L, mientras que las gramas Zoysia y Ciempiés fueron menos eficientes, con valores de 17.4 y 17.8 mg/L, respectivamente. Las concentraciones de N03-N no cambiaron significativamente para la grama Bermuda al aumentar el nivel de riego. Sin embargo, se obtuvieron menores concentraciones promedios anuales en Ciempiés y Zoysia con los niveles de riego de 100% y de 75%, respectivamente. La grama Bermuda obtuvo un buen índice de color, y reducción en la pérdida de N03-N en el nivel de riego de 100%. En contraste, las gramas Zoysia y Ciempiés presentaron un color aceptable y menor lixiviación de N03-N con el nivel de riego de 75%

Constraining the assembly time of the stellar haloes of nearby Milky Way-mass galaxies through AGB populations

The star formation histories (SFHs) of galactic stellar haloes offer crucial insights into the merger history of the galaxy and the effects of those mergers on their hosts. Such measurements have revealed that while the Milky Way's most important merger was 8-10 Gyr ago, M31's largest merger was more recent, within the last few Gyr. Unfortunately, the required halo SFH measurements are extremely observationally expensive outside of the Local Group. Here we use asymptotic giant branch (AGB) stars brighter than the tip of the red giant branch (RGB) to constrain stellar halo SFHs. Both stellar population models and archival datasets show that the AGB/RGB ratio constrains the time before which 90% of the stars formed, $t_{90}$. We find AGB stars in the haloes of three highly-inclined roughly Milky Way-mass galaxies with resolved star measurements from the Hubble Space Telescope; this population is most prominent in the stellar haloes of NGC 253 and NGC 891, suggesting that their stellar haloes contain stars born at relatively late times, with inferred $t_{90}\sim 6\pm1.5$Gyr. This ratio also varies from region to region, tending towards higher values along the major axis and in tidal streams or shells. By combining our measurements with previous constraints, we find a tentative anticorrelation between halo age and stellar halo mass, a trend that exists in models of galaxy formation but has never been elucidated before, i.e, the largest stellar haloes of Milky-Way mass galaxies were assembled more recently.Comment: 20 Pages, 10 Figure

Satellite Solar Insolation-Based Daily Evapotranspiration Estimation in Puerto Rico

ABSTRACT: A technique is presented in which satellite solar insolation estimates are used to predict daily reference evapotranspiration (ET o ) using the Penman-Monteith (PM), Preistly-Taylor (PT) and Hargreaves-Samini (HS) methods for Puerto Rico. For this approach, average, minimum and maximum daily air temperatures were obtained from a regression procedure that depends on surface elevation and day of the year. The air temperature was adjusted using actual daily temperatures from several locations in PR. Dew point temperature was assumed to be equal to the daily minimum temperature, and a value of 1.9 m/s was assumed for wind speed. As an example, ET o was estimated for March 5, 2009 using the three methods, with the Penman-Monteith method producing the lowest values. This research represents a preliminary step in the development of an ET o product for PR. This product is a potentially valuable tool for conducting water resource studies and for supporting irrigation scheduling efforts

COMPUTER PROGRAM FOR ESTIMATING CROP EVAPOTRANSPIRATION IN PUERTO RICO

COMPUTER PROGRAM FOR ESTIMATING CROP EVAPOTRANSPIRATION IN PUERTO RIC

Revaluación del coeficiente de evaporímetro en siete localidades en Puerto Rico

The goal of this project was to update pan evaporation coefficient (KP) values for the seven University of Puerto Rico Experimental Substations, based on updated pan evaporation data and the Penman-Monteith reference evapotranspiration. As a part of the study, historical pan evaporation data were evaluated from seven experimental substations. Significant decreasing pan evaporation was observed at Lajas and Río Piedras. Significant increasing pan evaporation was observed at Gurabo and Adjuntas, and no significant trends were observed at Fortuna, Isabela or Corozal. A significant difference was found to exist between the mean Kp values calculated with pan evaporation data from 1960 to 1980 and those with data from 1981 to 2000. El objetivo de este proyecto es actualizar los valores del coeficiente de evaporímetro (KP) en las siete subestaciones experimentales de la Universidad de Puerto Rico, basado en la ecuación de referencia de Penman-Monteith para la evapotranspiración. Como parte del estudio se evaluaron los datos históricos recolectados con evaporímetros en las siete subestaciones. Se observó una disminución significativa en la evaporación en Lajas y Río Piedras, mientras hubo un crecimiento significativo en la evaporación en Gurabo y Adjuntas; no hubo variación significativa en Fortuna, Isabela y Corozal. Se encontró diferencia significativa entre los valores de KP  calculados con datos del evaporímetro desde 1960 a 1980 y aquéllos con datos de 1981 a 2000