Data and code for: Springtime formation of laminated soil carbonate rinds and changes in fluvial terrace soils on orbital timescales at Rio Mesa, Utah, USA

Zenodo (CERN European Organization for Nuclear Research) · 2026-01-01

Data and analytical code for: Springtime formation of laminated soil carbonate rinds and changes in fluvial terrace soils on orbital timescales at Rio Mesa, Utah, USA

Data and code for: Springtime formation of laminated soil carbonate rinds and changes in fluvial terrace soils on orbital timescales at Rio Mesa, Utah, USA

Zenodo (CERN European Organization for Nuclear Research) · 2026-01-01 · 1 citations

Data and analytical code for: Springtime formation of laminated soil carbonate rinds and changes in fluvial terrace soils on orbital timescales at Rio Mesa, Utah, USA

Springtime Formation of Laminated Soil Carbonate Rinds and Changes in Fluvial Terrace Soils on Orbital Timescales at Rio Mesa, Utah, USA

Geochemistry Geophysics Geosystems · 2026-04-29

Abstract Laminated soil carbonate rinds are a Quaternary paleoclimate archive whose isotope composition is linked to soil formation conditions. At Rio Mesa, Utah (USA), we investigated the fidelity of rind records in a river terrace setting by determining the seasonal timing of rind formation and testing for inter‐record replication. We infer soil carbonate formed in the spring season, contrasting with our prior inference of summer formation at Teasdale, Utah, ≈200 km distant. This apparent discrepancy occurs because of differences in the timing of the largest annual infiltration (spring vs. summer). At Rio Mesa, modern soil data show that soil carbonate δ 13 C would have high values (−2 to 2‰ VPDB) regardless of seasonal activity of C 3 versus C 4 plants because respiration rate is a strong control. We accordingly suggest reassessment of published records interpreting soil carbonate δ 13 C only via C 3 versus C 4 plant abundance. Three rind δ 13 C and δ 18 O records generally replicated. Intriguingly, rind δ 13 C may inversely correlate with summer insolation, evidence for global‐scale influence on soils. Rind δ 18 O is not as clearly correlated with published western USA paleoclimate records, potentially due to regional differences in climate and because rinds record soil‐specific processes. Our results support the fidelity of the soil carbonate rind paleoarchive and suggest that because rind formation seasonality is intimately tied to infiltration seasonality, spatial transects of rind records might be used to delineate boundaries between areas dominated by spring and summer infiltration, permitting reconstruction of the geographic extent of large‐scale hydrologic phenomena such as the North American Monsoon.

Comment on egusphere-2025-452

2025-05-28

<strong class="journal-contentHeaderColor">Abstract.</strong> We investigate the role of short-term variability on the mean ecosystem exchange of carbon dioxide and water vapor. Specifically, we focus on quantifying how the intermittent turbulent exchange at the forest-atmosphere interphase &ndash; characterized by sweeps, ejections and outward/inward interactions &ndash; contributes to the mean exchange. To this end we analyze observations of high-resolution (isotopic) flux measurements taken at 25 m above the forest canopy at the Amazon Tall Tower Observatory (ATTO) during the dry season. We identify short-term turbulent eddies that eject carbon dioxide and water vapor from the understory (0&ndash;15 m) into the atmosphere. The H₂O ejected from the understory is shown to be depleted in deuterium (²H) by 10 &permil; compared to H₂O originating from the top canopy. We show that this matches the depleted water vapor isotopic compositions found in understory leaf and soil samples. The diurnal cycle of the net ecosystem exchange (NEE) of CO₂ is presented as a function of the sweeping and ejection motions and understory flux contributions. Understory contributions average 1.4 % of NEE, but reach up to 20 %. In exploring the connection between intermittent canopy turbulence and cloud passages, we found a weak but coherent temporal relationship (r = 0.027) between cloud passages and ejections, without a predominant influence of large clouds. These findings deepen our understanding of the gas exchange of the Amazon rainforest, which is urgent for predicting and possibly preventing the regions transition from a carbon sink to a source.

Using GNSS-based vegetation optical depth, tree sway motion, and eddy-covariance to examine evaporation of canopy-intercepted rainfall in a subalpine forest

2025-04-25

Abstract. Recent advances in the measurement of water content within a forest, have led to new possibilities to study canopy evaporation. We used a pair of Global Navigation Satellite System GNSS receivers (one above the canopy and one near the forest floor) to calculate the vegetation optical depth VOD during the warm season in a Colorado subalpine forest. One goal in our study was to compare VOD to the concurrent tree sway motion and subcanopy/above-canopy eddy-covariance evapotranspiration ET measurements. We found that VOD increased and tree sway frequency decreased during wet periods; furthermore, both measurements exhibited a linear relationship between each other and suggested that it took around 14 h after rainfall ceased for the intercepted rainwater to fully evaporate from the canopy. On dry days, we found that tree sway was more sensitive to diel changes in internal tree-water content than VOD. The ET measurements provided quantitative estimates of canopy evaporation (0.02 mm h−1 at night, to 0.08 mm h−1 during mid-day). Following rainfall, nighttime VOD, tree sway and ET all showed a steady (nearly constant) drying of the canopy. Variability in the VOD and tree sway measurements, comparisons with water content from the CLM4.5 land-surface model, and challenges with ET measurements, are also discussed.

Multi-laboratory compilation of atmospheric carbon dioxide data for the period 1957-2024; obspack_co2_1_GLOBALVIEWplus_v11.0_2026-01-12

Global Monitoring Laboratory · 2025-01-01

This product is constructed using the Observation Package (ObsPack) framework [Masarie et al., 2014; www.earth-syst-sci-data.net/6/375/2014/]. The framework is designed to bring together atmospheric greenhouse gas (GHG) observations from a variety of sampling platforms, prepare them with specific applications in mind, and package and distribute them in a self-consistent and well-documented product. ObsPack products are intended to support GHG budget studies and represent a new generation of cooperative value-added GHG data products. This product includes 679 atmospheric carbon dioxide datasets derived from observations made by 80 laboratories from 28 countries. Data for the period 1957-2024 (where available) are included.

Tracking subtle seasonal shifts in pigment composition with hyperspectral reflectance in a temperate evergreen forest

Tree Physiology · 2025-09-03 · 1 citations

Pigment dynamics in temperate evergreen forests remain poorly characterized, despite their year-round photosynthetic activity and importance for carbon cycling. Developing rapid, nondestructive methods to estimate pigment composition enables high-throughput assessment of plant acclimation states. In this study, we investigate the seasonality of eight chlorophyll and carotenoid pigments and hyperspectral reflectance data collected at both the needle (400-2400 nm) and canopy (420-850 nm) scales in longleaf pine (Pinus palustris Mill.) at the Ordway Swisher Biological Station in north-central Florida, USA. Needle spectra were obtained at three distinct times throughout the year, while tower-based spectra were collected continuously over a 9-month period. Seasonal trends in photoprotective pigments (e.g. lutein and xanthophylls) and photosynthetic pigments (e.g. chlorophylls) aligned closely with seasonal changes in photosynthetically active radiation and gross primary productivity. To track inter-tree and seasonal variability in pigment pools with hyperspectral reflectance data, we used correlation analyses and ridge regression models. Ridge regression models using the full hyperspectral range outperformed predictions using standard linear regression with specific wavelengths in a normalized difference index fashion. Ridge regression successfully predicted all pigment pools (R2 > 0.5) with comparable accuracy at both the needle and canopy scales. The models performed best for lutein, neoxanthin, antheraxanthin, and chlorophyll a and b-which had greater inter-tree and seasonal variation-and achieved moderate accuracy for violaxanthin, alpha-carotene and beta-carotene. These results provide a foundation for scaling biochemical traits from ground-based sensors to airborne and satellite platforms, particularly in ecosystems with subtle changes in pigment dynamics.

Can we characterize the effects of tree mortality from wildfire and bark beetles using satellite observations of solar-induced chlorophyll fluorescence?

SSRN Electronic Journal · 2025-01-01

Network of networks: Time series clustering of AmeriFlux sites

Agricultural and Forest Meteorology · 2025-06-24 · 2 citations

• Air temperature and net radiation followed a latitude gradient in clustering. • Clustering of fluxes was related to mean annual temperature and precipitation. • Site uniqueness was quantified, and proximal sites pairs were more similar. • Unique sites were in urban, open water, mountains, Hawaii, and Latin America. Environmental observation networks, such as AmeriFlux, are foundational for monitoring ecosystem response to climate change, management practices, and natural disturbances; however, their effectiveness depends on their representativeness for the regions or continents. We proposed an empirical, time series approach to quantify the similarity of ecosystem fluxes across AmeriFlux sites. We extracted the diel and seasonal characteristics (i.e., amplitudes, phases) from carbon dioxide, water vapor, energy, and momentum fluxes, which reflect the effects of climate, plant phenology, and ecophysiology on the observations, and explored the potential aggregations of AmeriFlux sites through hierarchical clustering. While net radiation and temperature showed latitudinal clustering as expected, flux variables revealed a more uneven clustering with many small (number of sites < 5), unique groups and a few large (> 100) to intermediate (15–70) groups, highlighting the significant ecological regulations of ecosystem fluxes. Many identified unique groups were from under-sampled ecoregions and biome types of the International Geosphere-Biosphere Programme (IGBP), with distinct flux dynamics compared to the rest of the network. At the finer spatial scale, local topography, disturbance, management, edaphic, and hydrological regimes further enlarge the difference in flux dynamics within the groups. Nonetheless, our clustering approach is a data-driven method to interpret the AmeriFlux network, informing future cross-site syntheses, upscaling, and model-data benchmarking research. Finally, we highlighted the unique and underrepresented sites in the AmeriFlux network, which were found mainly in Hawaii and Latin America, mountains, and at under-sampled IGBP types (e.g., urban, open water), motivating the incorporation of new/unregistered sites from these groups.

Supplementary material to "Using GNSS-based vegetation optical depth, tree sway motion, and eddy-covariance to examine evaporation of canopy-intercepted rainfall in a subalpine forest"

2025-04-25 · 1 citations