DOI: 10.5061/dryad.p2ngf1w3x
title: Seasonality of temperature dependence of methane fluxes from natural wetlands

description: Temperature dependence is a crucial parameter in estimating methane (CH4)
 fluxes from natural wetlands, yet our understanding of this parameter
 remains inadequate. Seasonal fluctuations in water levels and ecosystem
 productivity lead to seasonal differences in CH4 production and oxidation.
 We hypothesized the existence of seasonality in the temperature dependence
 of CH4 fluxes. To validate this hypothesis, we analyzed the FLUXNET-CH4
 dataset to determine the seasonal variation in temperature dependence of
 CH4 fluxes. We divided the year into six seasons based on air temperature
 and assessed the temperature dependence for each season using the apparent
 activation energy calculated by the Boltzmann-Arrhenius equation. Our
 results showed that temperature dependence showed a unimodal trend with
 seasons, with the apparent activation energy peaking in early summer (0.60
 eV), and reaching its lowest point in late winter (-0.02 eV). This
 seasonal pattern of temperature dependence was consistent across wetlands
 with different vegetation types and hydrological conditions. Modeling of
 global wetland CH4 emissions based on seasonal temperature dependences
 showed a 19% (4-45%) increase in emission rates under the most severe
 temperature rise scenario. Our results emphasize the seasonality of
 temperature dependence, which will help to further improve current and
 future predictions of wetland CH4 emissions.
description: # Seasonality of temperature dependence of methane fluxes from natural
 wetlands Data associated with: Journal Name: Functional Ecology Journal
 Code: FE Print ISSN: 0269-8463 Online ISSN: 1365-2435 Title: Seasonality
 of temperature dependence of methane fluxes from natural wetlands Authors:
 Li, Jinshuai; Hao, Tianxiang; Chen, Hongyang; Knox, Sara; Yang, Meng;
 Chen, Zhi; Yu, Guirui Contact Author: Tianxiang Hao (E-mail:
 [hao_tianxiang@163.com](mailto:hao_tianxiang@163.com)) ### Description of
 files and variables **1. List of variables in sheet 1 of ECdata.xlsx:** *
 NUM: Data counting * SITE_ID: Flux Site ID * CLASS: Wetland category *
 DOM_VEG: Vegetation category * LATITUDE: Site latitude * LONGITUDE: Site
 longitude * YEAR: Measurement year * MONTH: Measurement month * DAY:
 Measurement day * NUMBER: Data counting at stations within a year * TA:
 Air temperature, unit: ℃ * TS: Soil temperature, unit: ℃ * GPP: Gross
 primary productivity, unit: g/m2/d * RE: Rcosystem respiration, unit:
 g/m2/d * WTD: Water table depth, unit: m * NEE: Net ecosystem exchange,
 unit: g/m2/d * CH4: Methane emission rate, unit: g/m2/d **2. Temperature
 data for future climate scenarios: tas_day_NorESM2-MM_ssp585.zip** **DATA
 SOURCE** Global climate model: NorESM2‑MM (Norwegian Earth System Model
 version 2, medium‑resolution) Project: CMIP6 Native grid label: gn
 (Gaussian native ~1° atmosphere grid, 192 × 288) Experiment/Scenario:
 SSP5-8.5 Time coverage: 2015-01-01 to 2100-12-31 (daily) Calendar: 365_day
 / noleap (February 29 absent) **VARIABLE DEFINITIONS** * tas: Near surface
 (2 meter) air temperature, unit: K * lat: Latitude * lon: Longitude *
 time: Time coordinate, unit: day **FILE NAMING PATTERN**
 tas_day_NorESM2-MM_ssp585_r1i1p1f1_gn_YYYYMMDD-YYYYMMDD.nc where
 YYYYMMDD‑YYYYMMDD denotes the inclusive start and end dates stored inside
 the file. **NOTES** Terminology: '*_bnds' In CMIP style NetCDF
 files, any variable whose name ends with '_bnds' (e.g.,
 'time_bnds', 'lat_bnds', 'lon_bnds') stores
 the lower and upper bounds of the associated coordinate. For example,
 spatial ('lat', 'lon'): south-north or west-east edges
 of that cell, temporal ('time'): exact start and end of the time
 interval. Auxiliary Files: 'wget-20231003003144' Plain‑text log
 generated by the 'wget' download utility. It records the
 original URLs, timestamps, and checks used to retrieve the NetCDF data
 from the CMIP6 archive. The file contains no climate variables and can be
 deleted after verification, but retaining it helps reproduce or audit the
 download process.