{"title":"Atmospheric Dryness Dominates Afternoon Depression of Global Terrestrial Photosynthesis","authors":"Yue Liu, Josep Peñuelas, Alessandro Cescatti, Yongguang Zhang, Zhaoying Zhang","doi":"10.1029/2024gl110954","DOIUrl":null,"url":null,"abstract":"Satellite observations reveal a widespread afternoon depression of photosynthesis globally. Utilizing satellite observations and eddy covariance tower-based observations worldwide, we investigated the impact of climate factors on the diurnal patterns of ecosystem gross primary production (GPP). Our analysis revealed that the increase in vapor pressure deficit (VPD) shifts the diurnal peak of GPP activity to earlier morning hours, particularly in drylands and areas with short vegetation. After disentangling the strong correlations among VPD, temperature, and soil moisture, we unraveled that VPD emerges as the dominant driver contributing to the widespread afternoon depression of photosynthesis in terrestrial vegetation globally. However, Earth System Models (ESMs) systematically underestimate the significant role of VPD in regulating photosynthesis. Eight out of 10 ESMs exhibited a clear afternoon increase in photosynthesis, which was attributed to temperature. Our findings emphasize the need to enhance the negative effects of VPD on diurnal photosynthesis in ESMs.","PeriodicalId":12523,"journal":{"name":"Geophysical Research Letters","volume":"28 1","pages":""},"PeriodicalIF":4.6000,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Geophysical Research Letters","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1029/2024gl110954","RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
Satellite observations reveal a widespread afternoon depression of photosynthesis globally. Utilizing satellite observations and eddy covariance tower-based observations worldwide, we investigated the impact of climate factors on the diurnal patterns of ecosystem gross primary production (GPP). Our analysis revealed that the increase in vapor pressure deficit (VPD) shifts the diurnal peak of GPP activity to earlier morning hours, particularly in drylands and areas with short vegetation. After disentangling the strong correlations among VPD, temperature, and soil moisture, we unraveled that VPD emerges as the dominant driver contributing to the widespread afternoon depression of photosynthesis in terrestrial vegetation globally. However, Earth System Models (ESMs) systematically underestimate the significant role of VPD in regulating photosynthesis. Eight out of 10 ESMs exhibited a clear afternoon increase in photosynthesis, which was attributed to temperature. Our findings emphasize the need to enhance the negative effects of VPD on diurnal photosynthesis in ESMs.
期刊介绍:
Geophysical Research Letters (GRL) publishes high-impact, innovative, and timely research on major scientific advances in all the major geoscience disciplines. Papers are communications-length articles and should have broad and immediate implications in their discipline or across the geosciences. GRLmaintains the fastest turn-around of all high-impact publications in the geosciences and works closely with authors to ensure broad visibility of top papers.