Seasonal Changes in Radiometric Temperature of Rice Vegetative Cover
Other Title
水稻植被輻射溫度之季節變化
Journal
中華農藝
Journal Volume
8
Journal Issue
4
Pages
193-201
Date Issued
1998-10-16
Date
1998-10-16
Author(s)
Chwen-Ming Yang
楊純明
Abstract
Thermal infrared radiometry is a reliable technique for measuring temperature of vegetative cover. Vegetation (canopy) temperature can be incorporated into a crop growth model to evaluate soil moisture availability, leaf water potential, and plant water status. Field experiments were conducted to monitor and analyze seasonal changes in radiometric temperature of rice vegetative cover during cropping seasons of 1996-1998 in Taiwan, using the technique of thermal infrared imagery. Distribution of canopy temperature fluctuated with climatic conditions and also varied during growing periods, indicating that geometric structure and pigment composition changes as plants develop. Difference between maximum and minimum canopy temperatures was increased as plants aged, implying again an alteration of canopy structure and coloration with plant development. Further, canopy temperatures were lower than ambient temperatures throughout growth phases in both crops. Canopy temperature was positive correlated (R: = 0.6275) with ambient air temperature in the range of 22-36°C. Results indicate that rice maintains an effective heat-dissipating process (transpiration) under well- watered conditions, and the capacity was altered by changes of air temperature up to about 36°C. Extensive thermal infrared image observation over vegetative cover of rice crops have allowed the evaluation of the infrared remote-sensing method in radiometric temperature measurements.
熱紅線輻射測定爲現代遙測科技之一，由於具有即時、非破壞與高準確度等特性，近年來已廣泛應用於衷作物生產作業系統。除了作物植被溫度之快速偵（檢）測，亦可結合於作物生長模式之中，以估測土壤有效水分、葉片水分潛勢、及植體水分狀態。本研究乃利用紅外線輻射影像技術追踪及分析不同期作水稻（oryza sativa L. cv. Tainung 67）植被溫度之變化，探討植被溫度與周遭氣溫之關係。根據兩年四期田間試驗結果，發現植被溫度受到周遭氣環境之影響，且隨著生育進展而異，驗證了植被幾何構造及色素因植齡增進而改變的事實。又由植被最高溫與最低溫之差距隨著植體發育而增加的趨勢，再佐證了植被結構及色澤隨生育而複雜化的現象。在本試驗栽植期間，植被溫度均低於周遭氣溫，且呈現正相關（R2=0.6275）。換言之，在氣溫22-36℃範圍內，水稻植體均能視氣溫之變化適酌調整體溫。顯示了在田間正常灌水狀態下，稻株維持散熱功能（蒸散作用），而此一調適能力至少持續至氣溫36℃。結果也顯示，熱紅外線輻射遙測技術提供了一條觀測作物植被溫度變化的途徑，利用為改善作物栽培環境（凡引起植被溫度變化之環境因子）之有效工具。
Subjects
Seasonal change
Radiometric temperature
Canopy temperature
Vegetative covcr
Rice
季節變化
輻射溫度
植冠溫度
植被覆蓋
水稻
Publisher
中華農藝學會
Type
journal article
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