A review of research on ozone flux observation and stomatal uptake estimation over terrestrial ecosystems

Abstract

Ground鄄level ozone (O 3) is a major pollutant with adverse effects on plant growth and yield. The impact on plants is generally studied by controlling the O 3 concentration using the open top chamber (OTC) method. The effects of O 3 on ecosystems are studied by combining assessment models and indices, calculated using O 3 concentration or flux measurements over the vegetation. As these effects are related to the level of O 3 entering into the plant忆s gas exchange, compared with concentration鄄based indices, the O 3 stomatal flux鄄based indices are considered the better standards for evaluating the influence of O 3 on ecosystems. In China, the rapid industrialization and urbanization has resulted in elevated O 3 concentration which is threatening crop production and yields. Studies are required to elucidate the O 3 risk鄄assessment indices, including consideration for the status of the plant. In this paper, we analyze the advantages and disadvantages of two kinds of assessment indices. We then introduce several O 3 flux observation and stomatal uptake estimation methods at ecosystem scale. We also review the progress in O 3 flux observations, stomatal uptake estimations and risk assessment across different ecosystems. Additionally, we present case studies and the future prospects of O 3 research in China. Concentration鄄 based indices are easily observed and calculated, but these types of indices are often lacking sufficient, robust experimental design and data. In contrast, O 3 flux鄄based indices are difficult to obtain, although they incorporate the status of the ecosystem. The method used for measuring O 3 flux is mainly the eddy covariance technique, generally seen as the best modern technique. However, this method is inferior compared with CO 2 / H 2 O flux measurements. The lack of a fast鄄response

Discussion along Source Onlap Sequence Stratigraphy Model from Putaohua Oil Layer of Songfang Oilfield in the Northern Songliao Basin

“…The sequence stratigraphy theory [1,2] improved by many geological scientists' research work [3][4][5][6][7][8][9] has been successfully applied in the continental basin sequence [11][12][13][14][15], and plays an important role in oil and gas exploration and development. Now, most onlap sequence stratigraphy model for basin edge is inverse onlap, which the direction of onlay pinchout is opposite to source direction (Fig.…”