Irrigated Agriculture Significantly Modifies Seasonal Boundary Layer Atmosphere and Lower-Tropospheric Convective Environment
Irrigated Agriculture Significantly Modifies Seasonal Boundary Layer Atmosphere and Lower-Tropospheric Convective Environment
复制标题
灌溉农业显着改变季节性边界层大气和低对流层对流环境
DOI：
10.1175/jamc-d-23-0020.1
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发表时间：
2024
影响因子：
3
通讯作者：
Kosiba, Karen
中科院分区：
文献类型：
--
作者：
Lachenmeier, Emilee;Mahmood, Rezaul;Phillips, Chris;Nair, Udaysankar;Rappin, Eric;Pielke, Roger A.;Brown, William;Oncley, Steve;Wurman, Joshua;Kosiba, Karen
草原改造为灌溉和非灌溉农业对大平原地区的天气和气候产生了重大影响。然而，目前还缺乏基于观测数据的研究，仅关注灌溉对PBL和对流条件的影响。大平原灌溉试验（GRAINEX）在2018年生长季节进行，收集了内布拉斯加州灌溉和非灌溉土地使用的数据，以了解这些影响。具体来说，目的是确定灌溉的影响是否在整个生长季节持续。分析的数据包括潜热和感热通量、气温、露点温度、等效温度（湿焓）、PBL高度、升力凝结水平（LCL）、自由对流水平（LFC）和PBL混合比。结果表明：从生长季早期到生长季高峰，灌区平均最高气温降低，露点温度升高，潜热的能量分配相对于感热增加；无线电探空数据表明，从早期到生长旺季，所有发射场的行星边界层（PBL）高度都有所降低。灌溉区PBL高度下降幅度明显大于非灌溉区。灌区生育高峰期的LCL和LFC高度均低于生育期前期。结果首次表明，灌溉对PBL演变和对流环境的影响可以持续整个生长季节，而不受背景大气条件的影响。这些都是重要的发现，适用于世界上其他灌区。为了满足日益增长的粮食需求，世界上许多地区已广泛采用灌溉方式。高平原含水层（HPA）地区，位于美国大平原，是最广泛的灌溉地区之一。在这项研究中，我们首次进行了详细的以灌溉为重点的地表和大气数据收集活动，以确定灌溉对大气的影响。本研究表明，灌溉显著改变了低层大气特征，并在生长季节创造了有利的云和对流发展条件。结果清楚地显示了灌溉对区域天气和气候的一级影响，因此值得进一步关注，以尽量减少负面影响，实现可持续灌溉。
Modification of grasslands into irrigated and nonirrigated agriculture in the Great Plains resulted in significant impacts on weather and climate. However, there has been lack of observational data–based studies solely focused on impacts of irrigation on the PBL and convective conditions. The Great Plains Irrigation Experiment (GRAINEX), conducted during the 2018 growing season, collected data over irrigated and nonirrigated land uses over Nebraska to understand these impacts. Specifically, the objective was to determine whether the impacts of irrigation are sustained throughout the growing season. The data analyzed include latent and sensible heat flux, air temperature, dewpoint temperature, equivalent temperature (moist enthalpy), PBL height, lifting condensation level (LCL), level of free convection (LFC), and PBL mixing ratio. Results show increased partitioning of energy into latent heat relative to sensible heat over irrigated areas while average maximum air temperature was decreased and dewpoint temperature was increased from the early to peak growing season. Radiosonde data suggest reduced planetary boundary layer (PBL) heights at all launch sites from the early to peak growing season. However, reduction of PBL height was much greater over irrigated areas than over nonirrigated croplands. Relative to the early growing period, LCL and LFC heights were also lower during the peak growing period over irrigated areas. Results note, for the first time, that the impacts of irrigation on PBL evolution and convective environment can be sustained throughout the growing season and regardless of background atmospheric conditions. These are important findings and applicable to other irrigated areas in the world.Significance StatementTo meet the ever-increasing demand for food, many regions of the world have adopted widespread irrigation. The High Plains Aquifer (HPA) region, located within the Great Plains of the United States, is one of the most extensively irrigated regions. In this study, for the first time, we have conducted a detailed irrigation-focused land surface and atmospheric data collection campaign to determine irrigation impacts on the atmosphere. This research demonstrates that irrigation significantly alters lower atmospheric characteristics and creates favorable cloud and convection development conditions during the growing season. The results clearly show first-order impacts of irrigation on regional weather and climate and hence warrant further attention so that we can minimize negative impacts and achieve sustainable irrigation.