Estimation of Sensible and Latent Heat Fluxes Using Surface Renewal Method: Case Study of a Tea Plantation

An experiment of sensible and latent heat flux measurement was conducted in a tea plantation near the Yangtze River within Danyang of Jiangsu Province, China. High-frequency (~10 Hz) air temperature measurement with fine-wire thermocouples (⌀ = 50 μm) was used for the estimation of sensible heat flux (H), and latent heat flux (LE) was extracted as a residual of the energy balance equation using additional measurements of net radiation (Rn) and soil heat flux (G). Results were compared against the eddy covariance (EC) system under unstable conditions only, and days with high precipitation were excluded from further analysis. Half-hourly datasets of the sensible heat flux estimated using the surface renewal method (SR) (HSR) and measured by the EC system (HEC) were analyzed. Results showed good agreement with R2 = 0.80, root mean square error (RMSE) = 27.87 W m−2, relative error (RE) = 9.02%, and a regression slope of 0.68—this slope was used for the calibration of the uncalibrated HSR estimated by SR. On the other hand, the half-hourly dataset of LESR was regressed against EC, and it showed good agreement with relatively high R2 = 0.93, RMSE = 32.99 W·m−2, and RE = 5.67%. Hence, the SR method may estimate the surface fluxes at a relatively low cost, ultimately improving calculations of evapotranspiration. Thus, the SR method could provide an economical tool for improving crop water management of tea plantations.

Evaluation of the Surface Renewal Method for Estimating Cotton Evapotranspiration in South Carolina

HighlightsThe Surface Renewal (SR), Eddy Covariance (EC), and FAO56 methods were used to estimate crop evapotranspiration.An independently calibrated SR approach was used with a low-cost cup anemometer and assumed energy balance closure.All three approaches (SR, EC, and FAO56) resulted in similar crop ET values during later stages of growth (R2 = 0.87).SR has the potential to lower field-scale ET measurement costs and equipment requirements.Abstract. Evapotranspiration (ET) is important for many agricultural and hydrological applications, but its measurement normally requires expensive instrumentation. The Surface Renewal method (SR) has been proposed as a relatively low-cost alternative to measure ET, but the need for local calibration has been cited as a shortcoming. Castellví (2004)(2004) proposed a similarity-based SR approach to address this shortcoming, but field comparisons evaluating the accuracy of the approach using low-cost anemometry are currently lacking. The objective of this study was to evaluate the reliability of the similarity-based SR approach using low-cost anemometry (cup anemometer) for estimating cotton ET in comparison to the Eddy Covariance (EC) and FAO56 methods (Allen et al., 1998). Concurrent estimates of cotton ET were taken in 2019 at two adjacent cotton fields in South Carolina using the SR, EC, and FAO56 methods. SR and EC measurements of sensible heat flux were replicated using two in-field tower locations in the north field and ET was derived using the energy balance closure approach. An analysis was made to ensure =90% of the EC and SR seasonal data came from the field area (Kljun et al., 2015), with additional filtering to ensure that the higher-mounted EC had >90% footprint from the field area for each half-hour of analysis. In general, the results showed very good agreement between the daily crop ET values measured by SR and EC (R2north = 0.93, R2south = 0.97) for all of the season, and good agreement between SR and FAO56 measurements when crop height was more developed (R2north = 0.92, R2south = 0.87), near or above a canopy height of 0.75 m. There was disagreement between the non-continuous north tower SR measurements and FAO56 measurements in earlier stages of growth (June and July R2 = 0.09), which may have been due to uncertainty with the FAO56 local single crop coefficients or with a lack of energy balance closure. The results suggest that the use of low-cost anemometry with the independently calibrated SR approach is a useful alternative to measure crop ET under the conditions of this study, but further research may be necessary to evaluate the use of low-cost anemometry for direct SR ET measurements. Keywords: Cotton irrigation, Crop coefficients, Eddy covariance, Evapotranspiration, ET, Surface renewal.

LAMPU HIAS DENGAN DEKORASI MOTIF BATIK PARANG DAN KAWUNG INOVASI PENCIPTAAN KERAMIK

ABSTRACTProduct innovation is a strategy that must be carried out by(UMKM) in the craft business in order to always have a competitive advantage. This research is a discussion to get ceramic products that have an assessment of Indonesia so that they can compete in the global market. Parang and Kawung traditional batik motifs representing the freedom of choice of Indonesia were chosen as a form of innovation that was tried to be mixed with ceramic decorative lighting products. This batik motif is not only placed on ceramic decorative lighting products, but will be made together and become a part or character of the ceramics. This study uses a renewal method in the design of ceramic products, starting from the exploration of trends, analysis, sketching, and the last is per work design drawings or designs. Embodiment or production is done by experimentation to get the right material composition, technique, and production method or process. It will also conduct a market test by exhibiting prototype products in art-shops owned by ceramic craftsmen.The research target in the first year is the creation of techniques or production methods, and 10 ceramic designs that are in accordance with market trends and tastes. In the second year the creation of 10 prototype products and submitted to IPR, approved scientific articles, and market testing. The results of this study are expected to help craftsmen diversify their products to increase sales for the export market.ABSTRAKInovasi produk adalah strategi yang harus terus dilakukan oleh usaha mikro kecil menengah (UMKM) kerajinan agar selalu memiliki keunggulan kompetitif. Penelitian ini adalah sebuah eksplorasi penciptaan untuk mendapatkan produk keramik yang memiliki nuansa etnis Indonesia sehingga dapat berkompetisi pada pasar global. Motif batik tradisional Parang dan Kawung mewakili nuansa etnis Indonesia dipilih sebagai bentuk inovasi yang dicoba untuk di-mix-kan dengan produk lampu hias keramik. Motif batik tersebut tidak hanya sekedar ditempelkan pada produk lampu hias keramik, akan tetapi dibuat menyatu dan menjadi bagian atau karakter dari keramik tersebut. Penelitian ini menggunakan metode pendekatan estetis dalam merancang desain produk keramik, dimulai dari ekplorasi trend, analisis, pembuatan sketsa, serta yang terakhir adalah perancangan gambar kerja atau desain. Perwujudan atau produksi dilakukan dengan eksperimentasi untuk mendapatkan komposisi bahan, teknik, dan metode atau proses produksi yang tepat. Selain itu juga akan dilakukan uji pasar (market test) dengan memamerkan produk prototype di art-shop yang dimiliki oleh pengrajin keramik. Target penelitian pada tahun pertama adalah terciptanya teknik atau metode produksi, dan 10 desain keramik yang sesuai dengan trend dan selera pasar. Pada tahun ke dua terciptanya 10 produk prototype dan mendaftarkan ke HKI, penerbitan artikel ilmiah, serta uji pasar. Hasil penelitian tersebut diharapkan dapat membantu para pengrajin melakukan diversifikasi produk guna meningkatkan penjualan terutama untuk pasar ekspor.

SANITARY SEWER CONSTRUCTION COST COMPARISON BETWEEN TRENCHLESS CIPP RENEWAL AND OPEN-CUT REPLACEMENT

Renewal and replacement of aging underground infrastructure, which mainly includes pipelines is one of the vital issues for the North American municipalities every day. Conventional replacement of these aging pipelines utilizes open-cut trenching methods that could be expensive both in rural and urban areas. In trenchless cured-in-place pipe (CIPP) pipeline renewal method, a liquid thermoset resin-saturated material is put inside the deteriorated pipe by hydrostatic, air inversion, or pulling inside mechanically and inflating. Then, the curing of the liner material used could be done in-place using three different ways such as, hot water, steam-or UV-cured to result in a final cured product. Trenchless methods are considered much more cost-effective. However, to make a comprehensive comparison, engineers and project owners will benefit from additional data. The objective of this study is to review past studies dealing with CIPP renewal method and open-cut pipeline replacement, and to compare their construction costs for renewing the small, medium, and large diameter sanitary sewer pipelines with the help of statistical analysis. It was found that mean construction costs of CIPP renewal is 57%, 63%, and 18% less as compared to the open-cut pipeline replacement for small, medium, and large diameter sanitary sewer pipes, respectively. It can be concluded that using CIPP method, municipalities can save millions of dollars in the renewal of underground utility systems. A life cycle cost analysis to evaluate and compare the construction, environmental, and social costs between CIPP renewal method and open-cut pipeline replacement is recommended.

Calibration of the Surface Renewal Method (SR) under Different Meteorological Conditions in an Avocado Orchard

The surface renewal method (SR) allows estimating the sensible heat flux (H) using high-frequency thermocouples. Traditionally, SR has been compared and calibrated using standard instruments such as the Eddy covariance system (EC). Calibration involves correcting H measured with SR (H’SR) by means of the calibration factor (α). However, several studies show that α is not constant and could depend on canopy architecture, measurement height, atmospheric stability, and weather conditions. In avocado orchards, there is not enough information about energy fluxes and the application of the SR method. Therefore, the objective of this study is to calibrate the SR method in a mature avocado orchard considering the effect of meteorological conditions on the determination of α. The components of the surface energy balance were measured using an EC system in a commercial avocado orchard (cv. Hass) located in the Aconcagua Valley, Valparaíso Region, Chile. To evaluate the effect of the meteorological conditions on the determination of α, the dataset was classified into nine categories based on solar radiation and wind intensity. The results show that α varies according to meteorological conditions, with significant differences for cloudy days. The use of the variable α reduced the error in estimating H, so, this methodology can be used to have a more precise approximation of the energy balance and therefore to the water requirements.