Utilização da equação de Hargreaves Samani para o cálculo da ETo em estufas

PosterA equação de Hargreaves Samani, HS, tem sido utilizada com sucesso para o cálculo da Evapotranspiração, Eto, ao ar livre. Os resultados indicam uma boa correlação entre a Eto obtida por este método e a obtida pelo método de Penman-Monteith, PM, que exige um conjunto maior de parâmetros. Até a data pouco se sabe sobre a aplicabilidade da equação de HS em agricultura protegida. Neste ensaio foram instalados minilisimetros numa estufa na Herdade de Mitra, Évora. A cultura utilizada foi a relva, por forma a eliminar a necessidade de determinação exacta do coeficiente cultural. Foram medidos em intervalos de 15 minutos a Temperatura do ar, radiação, Humidade Relativa e o vento no interior e exterior da estufa. A equação de HS foi calibrada com base nos valores dos lisimetros e com base na equação de PM. Os resultados indicam que no interior da estufa há uma diminuição da radiação em 44%, e o aumento da temperatura máxima em 2,4ºC e da temperatura mínima em 3,7ºC. A utilização da estufa permitiu uma poupança de água de 42% A equação de HS resulta em boas estimativas de Eto, desde que seja devidamente calibrada para a radiação no interior da estufa. A inclusão da radiação no cálculo da Eto pela equação de HS não melhora os resultados--------------------------ABSTRACT----The Hargreaves Samani equation, HS, has been used successfully for calculating Evapotranspiration, Eto, in open air. The results indicate a good correlation between Eto obtained with this method and that obtained through the Penman- Monteith, PM, method, which requires a larger number of parameters. Until now, little is known about the use of the HS equation in greenhouses. In this work, mini-lysimeters were installed in a greenhouse at the Mitra Experimental Farm, in Évora. Lawn was used as the crop, in order to eliminate the need for the exact determination of the crop coefficient. Air temperature, radiation, relative humidity and wind were measured at 15 minute intervals inside and outside of the greenhouse. The HS equation was calibrated based on the values from the lysimeters and the PM equation. The results indicate that inside the greenhouse the radiation decreases by 44%, maximum temperature increases by 2.4ºC and the minimum temperature by 3,7ºC. The use of greenhouse resulted in a water saving of 42%. The HS equation results in good estimates of Eto once it has been calibrated for the radiation intensity inside the greenhouse. The inclusion of the radiation in the calculation of Eto by the HS equation did not improve the results

Semi-empirical catalog of early-type galaxy-halo systems: dark matter density profiles, halo contraction and dark matter annihilation strength

With SDSS galaxy data and halo data from up-to-date N-body simulations we construct a semi-empirical catalog (SEC) of early-type systems by making a self-consistent bivariate statistical match of stellar mass (M_star) and velocity dispersion (sigma) with halo virial mass (M_vir). We then assign stellar mass profile and velocity dispersion profile parameters to each system in the SEC using their observed correlations with M_star and sigma. Simultaneously, we solve for dark matter density profile of each halo using the spherical Jeans equation. The resulting dark matter density profiles deviate in general from the dissipationless profile of NFW or Einasto and their mean inner density slope and concentration vary systematically with M_vir. Statistical tests of the distribution of profiles at fixed M_vir rule out the null hypothesis that it follows the distribution predicted by N-body simulations for M_vir ~< 10^{13.5-14.5} M_solar. These dark matter profiles imply that dark matter density is, on average, enhanced significantly in the inner region of halos with M_vir ~< 10^{13.5-14.5} M_solar supporting halo contraction. The main characteristics of halo contraction are: (1) the mean dark matter density within the effective radius has increased by a factor varying systematically up to ~ 3-4 at M_vir = 10^{12} M_solar, and (2) the inner density slope has a mean of ~ 1.3 with rho(r) ~ r^{-alpha} and a halo-to-halo rms scatter of rms(alpha) ~ 0.4-0.5 for 10^{12} M_solar ~< M_vir ~< 10^{13-14} M_solar steeper than the NFW profile (alpha=1). Based on our results we predict that halos of nearby elliptical and lenticular galaxies can, in principle, be promising targets for gamma-ray emission from dark matter annihilation.Comment: 43 pages, 20 figures, JCAP, revised and accepted versio