Determining regional scale carbon losses from tropical peatlands using ISBAS-InSAR

80% of peatlands in Indonesia and Malaysia (15% of Earth's soil carbon) are now drained for production of pulp wood and palm oil. Associated increased peat decomposition and large-scale forest fires are now significant contributors to global greenhouse gas emissions. However, carbon losses from these processes and the impact of peatland drainage remain poorly quantified across SE Asia because of the challenging scale and inaccessibility of dense tropical peatland forests.Space-based platforms offer the opportunity for regular and efficient pan-regional monitoring and overcome inaccessibility of tropical peatland environments. A development in satellite&#160;interferometric synthetic aperture radar (InSAR) in monitoring surface motion has the potential to solve this problem. A new &#8216;intermittent small baseline subset&#8217;&#160;(ISBAS) modelling technique provides excellent coverage across almost all land surfaces irrespective of ground cover, enabling long-term measurement of peatland surface motion across whole catchments, regions and countries. Importantly, the ISBAS technique is able to determine surface deformation under tropical forest canopy using C-band&#160;InSAR, enabling continuous&#160;monitoring of surface motion ranging from 0.1&#8211;40cm/yr&#160;at spatial scales&#160;&#8805;90x90m.This project aims to determine whether rate of subsidence of the peat surface measured by&#160;ISBAS-InSAR&#160;is a proxy for rate of carbon loss in&#160;tropical peatlands in SE Asia. ISBAS-InSAR&#160;time series and field measurements of subsidence&#160;will be used to monitor and characterise seasonal tropical peat surface oscillations over time and field radar experiments will investigate C-band radar signal attenuation with the peat surface at different moisture contents.

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Fluvial organic carbon fluxes from oil palm plantations on tropical peatland

Biogeosciences ◽

10.5194/bg-15-7435-2018 ◽

2018 ◽

Vol 15 (24) ◽

pp. 7435-7450 ◽

Cited By ~ 7

Author(s):

Sarah Cook ◽

Mick J. Whelan ◽

Chris D. Evans ◽

Vincent Gauci ◽

Mike Peacock ◽

...

Keyword(s):

Organic Carbon ◽

Oil Palm ◽

Carbon Sources ◽

Total Carbon ◽

Land Conversion ◽

Tropical Peatland ◽

Oil Palm Plantation ◽

Tropical Peatlands ◽

Carbon Losses

Abstract. Intact tropical peatlands are dense long-term stores of carbon. However, the future security of these ecosystems is at risk from land conversion and extensive peatland drainage. This can enhance peat oxidation and convert long-term carbon sinks into significant carbon sources. In Southeast Asia, the largest land use on peatland is for oil palm plantation agriculture. Here, we present the first annual estimate of exported fluvial organic carbon in the drainage waters of four peatland oil palm plantation areas in Sarawak, Malaysia. Total organic carbon (TOC) fluxes from the plantation second- and third-order drains were dominated (91 %) by dissolved organic carbon (DOC) and ranged from 34.4 ± 9.7 C m−2 yr−1 to 57.7 %, 16.3 g C m−2 yr−1 (± 95 % confidence interval). These fluxes represent a single-year survey which was strongly influenced by an El Ninõ event and therefore lower discharge than usual was observed. The magnitude of the flux was found to be influenced by water table depth, with higher TOC fluxes observed from more deeply drained sites. Radiocarbon dating on the DOC component indicated the presence of old (pre-1950s) carbon in all samples collected, with DOC at the most deeply drained site having a mean age of 735 years. Overall, our estimates suggest fluvial TOC contributes ∼ 5 % of total carbon losses from oil palm plantations on peat. Maintenance of high and stable water tables in oil palm plantations appears to be key to minimising TOC losses. This reinforces the importance of considering all carbon loss pathways, rather than just CO2 emissions from the peat surface, in studies of tropical peatland land conversion.

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Impact of fire on vegetation, soil microbes and CH4 emission from a degraded tropical peatland

10.5194/egusphere-egu2020-12743 ◽

2020 ◽

Cited By ~ 1

Author(s):

Hasan Akhtar ◽

Massimo Lupascu ◽

Omkar S. Kulkarni ◽

Aditya Bandla ◽

Rahayu S. Sukri ◽

...

Keyword(s):

Southeast Asia ◽

Water Table ◽

Vegetation Structure ◽

High Throughput Sequencing ◽

Microbial Community Composition ◽

Tropical Peatland ◽

Tropical Peatlands ◽

Peat Profile ◽

The Impact

Over the past few decades, tropical peatlands in Southeast Asia have been heavily degraded for multiple land uses, mainly by employing drainage and fire. More importantly, the extent of these degraded areas, primarily covered with ferns and sedges, have increased to almost 10% of the total peatland area in Southeast Asia. In particular, the role of sedges in plant-mediated gas transport to the atmosphere has been recognized as a significant CH4 pathway in northern peatlands, however, in the Tropics this is still unknown. Within this context, we adopted an integrated approach using on-site measurements (CH4, porewater physicochemical characteristics) with genomics to investigate the role of hydrology, vegetation structure, and microbiome on CH4 emission from fire-degraded tropical peatland in Brunei.&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; We found for the first time that in degraded tropical peatlands of Southeast Asia, sedges transported 70-80% of the total CH4 emission and significantly varied with values ranging from 1.22&#177;0.13 to 6.15&#177;0.57 mg CH4 m-2 hr-1, during dry and wet period, respectively. This variation was mainly attributed to water table position along with changes in sedge cover and porewater properties, which created more optimal methanogenesis conditions. Total emissions via this process might increase in the future as the extent of degraded tropical peatlands expands due to more frequent fire episodes and flooding.&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; Further, we used 16S rRNA high-throughput sequencing to investigate the microbiomes in peat profile (above and below water table) as well as rhizo-compartments (Rhizosphere, Rhizoplane, Endosphere) of sedges. We found that the peat profile as well as rhizo-compartments of sedge harboured a higher number of methanogenic archaea in the order Methanomicrobiales and Methanobacteriales, compared to non-burnt and bulk soil, which further explains our findings of higher CH4 emission from degraded tropical peatland areas covered with sedges. These insights into the impact of fire on hydrology, vegetation structure, and microbial community composition on CH4 emissions provide an important basis for future studies on CH4 dynamics in degraded tropical peatland areas.

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Fluvial organic carbon fluxes from oil palm plantations on tropical peatland

10.5194/bg-2018-417 ◽

2018 ◽

Cited By ~ 1

Author(s):

Sarah Cook ◽

Mick J. Whelan ◽

Chris D. Evans ◽

Vincent Gauci ◽

Mike Peacock ◽

...

Keyword(s):

Organic Carbon ◽

Oil Palm ◽

Carbon Sources ◽

Total Carbon ◽

Land Conversion ◽

Tropical Peatland ◽

Oil Palm Plantation ◽

Tropical Peatlands ◽

Carbon Losses

Abstract. Intact tropical peatlands are dense, long-term stores of carbon. However, the future security of these ecosystems is at risk from land conversion and extensive peatland drainage. This can enhance peat oxidation and convert long-term carbon sinks into significant carbon sources. In Southeast Asia, the largest land use on peatland is for oil palm plantation agriculture. Here, we present the first annual estimate of exported fluvial organic carbon in the drainage waters of four peatland oil palm plantation areas in Sarawak, Malaysia. Total organic carbon (TOC) fluxes from the plantation second and third order drains were dominated by dissolved organic carbon (DOC) and ranged from 34.4 ± 9.7 C m−2 yr−1 to 57.7 ± 16.3 g C m−2 yr−1 (± 95 % confidence interval). The magnitude of the flux was found to be influenced by water table depth, with higher TOC fluxes observed from more deeply drained sites. Radiocarbon dating on the DOC component indicated the presence of old (pre-1950s) carbon in all samples collected, with DOC at the most deeply drained site having a mean age of 735 years. Overall, our estimates suggest fluvial TOC contributes ~ 5 % of total carbon losses from oil palm plantations on peat. Maintenance of high and stable water tables in oil palm plantations appears to be key to minimising TOC losses. This reinforces the importance of considering all carbon loss pathways, rather than just CO2 emissions from the peat surface, in studies of tropical peatland land conversion.

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The impact of geolocation uncertainty on GEDI tropical forest canopy height estimation and change monitoring

Science of Remote Sensing ◽

10.1016/j.srs.2021.100024 ◽

2021 ◽

pp. 100024

Author(s):

David P. Roy ◽

Herve B. Kashongwe ◽

John Armston

Keyword(s):

Tropical Forest ◽

Forest Canopy ◽

Canopy Height ◽

Height Estimation ◽

The Impact ◽

Change Monitoring ◽

Tropical Forest Canopy

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Ears in the Sky: Potential of Drones for the Bioacoustic Monitoring of Birds and Bats

Drones ◽

10.3390/drones5010009 ◽

2021 ◽

Vol 5 (1) ◽

pp. 9

Author(s):

Adrien Michez ◽

Stéphane Broset ◽

Philippe Lejeune

Keyword(s):

Forest Canopy ◽

Low Cost ◽

Population Monitoring ◽

Biodiversity Loss ◽

Active Species ◽

Terrestrial Mammals ◽

Technical Developments ◽

High Resolution Imagery ◽

Human Operators ◽

The Impact

In the context of global biodiversity loss, wildlife population monitoring is a major challenge. Some innovative techniques such as the use of drones—also called unmanned aerial vehicle/system (UAV/UAS)—offer promising opportunities. The potential of UAS-based wildlife census using high-resolution imagery is now well established for terrestrial mammals or birds that can be seen on images. Nevertheless, the ability of UASs to detect non-conspicuous species, such as small birds below the forest canopy, remains an open question. This issue can be solved with bioacoustics for acoustically active species such as bats and birds. In this context, UASs represent an interesting solution that could be deployed on a larger scale, at lower risk for the operator, and over hard-to-reach locations, such as forest canopies or complex topographies, when compared with traditional protocols (fixed location recorders placed or handled by human operators). In this context, this study proposes a methodological framework to assess the potential of UASs in bioacoustic surveys for birds and bats, using low-cost audible and ultrasound recorders mounted on a low-cost quadcopter UAS (DJI Phantom 3 Pro). The proposed methodological workflow can be straightforwardly replicated in other contexts to test the impact of other UAS bioacoustic recording platforms in relation to the targeted species and the specific UAS design. This protocol allows one to evaluate the sensitivity of UAS approaches through the estimate of the effective detection radius for the different species investigated at several flight heights. The results of this study suggest a strong potential for the bioacoustic monitoring of birds but are more contrasted for bat recordings, mainly due to quadcopter noise (i.e., electronic speed controller (ESC) noise) but also, in a certain manner, to the experimental design (use of a directional speaker with limited call intensity). Technical developments, such as the use of a winch to safely extent the distance between the UAS and the recorder during UAS sound recordings or the development of an innovative platform, such as a plane–blimp hybrid UAS, should make it possible to solve these issues.

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Exploring the impact of introducing a physical model into statistical methods on the evaluation of regional scale debris flow susceptibility

Natural Hazards ◽

10.1007/s11069-020-04498-4 ◽

2021 ◽

Vol 106 (1) ◽

pp. 881-912

Author(s):

Jingbo Sun ◽

Shengwu Qin ◽

Shuangshuang Qiao ◽

Yang Chen ◽

Gang Su ◽

...

Keyword(s):

Debris Flow ◽

Physical Model ◽

Statistical Methods ◽

Regional Scale ◽

The Impact ◽

Debris Flow Susceptibility

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Reservoir-Induced Land Deformation: Case Study from the Grand Ethiopian Renaissance Dam

Remote Sensing ◽

10.3390/rs13050874 ◽

2021 ◽

Vol 13 (5) ◽

pp. 874

Author(s):

Yu Chen ◽

Mohamed Ahmed ◽

Natthachet Tangdamrongsub ◽

Dorina Murgulet

Keyword(s):

Land Surface ◽

Large Scale ◽

Surface Deformation ◽

Vertical Displacement ◽

Nile River ◽

Reservoir Volume ◽

Novel Approach ◽

Land Deformation ◽

Large Scale Land ◽

The Impact

The Nile River stretches from south to north throughout the Nile River Basin (NRB) in Northeast Africa. Ethiopia, where the Blue Nile originates, has begun the construction of the Grand Ethiopian Renaissance Dam (GERD), which will be used to generate electricity. However, the impact of the GERD on land deformation caused by significant water relocation has not been rigorously considered in the scientific research. In this study, we develop a novel approach for predicting large-scale land deformation induced by the construction of the GERD reservoir. We also investigate the limitations of using the Gravity Recovery and Climate Experiment Follow On (GRACE-FO) mission to detect GERD-induced land deformation. We simulated three land deformation scenarios related to filling the expected reservoir volume, 70 km3, using 5-, 10-, and 15-year filling scenarios. The results indicated: (i) trends in downward vertical displacement estimated at −17.79 ± 0.02, −8.90 ± 0.09, and −5.94 ± 0.05 mm/year, for the 5-, 10-, and 15-year filling scenarios, respectively; (ii) the western (eastern) parts of the GERD reservoir are estimated to move toward the reservoir’s center by +0.98 ± 0.01 (−0.98 ± 0.01), +0.48 ± 0.00 (−0.48 ± 0.00), and +0.33 ± 0.00 (−0.33 ± 0.00) mm/year, under the 5-, 10- and 15-year filling strategies, respectively; (iii) the northern part of the GERD reservoir is moving southward by +1.28 ± 0.02, +0.64 ± 0.01, and +0.43 ± 0.00 mm/year, while the southern part is moving northward by −3.75 ± 0.04, −1.87 ± 0.02, and −1.25 ± 0.01 mm/year, during the three examined scenarios, respectively; and (iv) the GRACE-FO mission can only detect 15% of the large-scale land deformation produced by the GERD reservoir. Methods and results demonstrated in this study provide insights into possible impacts of reservoir impoundment on land surface deformation, which can be adopted into the GERD project or similar future dam construction plans.

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Aerosol distribution over Europe: a model evaluation study with detailed aerosol microphysics

Atmospheric Chemistry and Physics ◽

10.5194/acp-8-1591-2008 ◽

2008 ◽

Vol 8 (6) ◽

pp. 1591-1607 ◽

Cited By ~ 36

Author(s):

B. Langmann ◽

S. Varghese ◽

E. Marmer ◽

E. Vignati ◽

J. Wilson ◽

...

Keyword(s):

Organic Carbon ◽

Rural Areas ◽

Regional Scale ◽

Evaluation Study ◽

Emission Data ◽

Aerosol Model ◽

Fire Emissions ◽

Elevated Ozone ◽

Emission Fluxes ◽

The Impact

Abstract. This paper summarizes an evaluation of model simulations with a regional scale atmospheric climate-chemistry/aerosol model called REMOTE, which has been extended by a microphysical aerosol module. Model results over Europe are presented and compared with available measurements in surface air focusing on the European distribution and variability of primary and secondary aerosols. Additionally, model results obtained with detailed aerosol microphysics are compared to those based on an aerosol bulk mass approach revealing the impact of dry deposition fluxes on atmospheric burden concentration. An improved determination of elevated ozone and sulfate concentrations could be achieved by considering a diurnal cycle in the anthropogenic emission fluxes. Deviation between modelled and measured organic carbon concentrations can be mainly explained by missing formation of secondary organic aerosols and deficiencies in emission data. Changing residential heating practices in Europe, where the use of wood is no longer restricted to rural areas, need to be considered in emission inventories as well as vegetation fire emissions which present a dominant source of organic carbon.

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Antarctic sea-ice thickness and volume estimates from ice charts between 1995 and 1998

Annals of Glaciology ◽

10.3189/2015aog69a763 ◽

2015 ◽

Vol 56 (69) ◽

pp. 383-393 ◽

Cited By ~ 3

Author(s):

E. Rachel Bernstein ◽

Cathleen A. Geiger ◽

Tracy L. Deliberty ◽

Mary D. Lemcke-Stampone

Keyword(s):

Sea Ice ◽

Regional Scale ◽

Weighted Average ◽

Ice Thickness ◽

Average Thickness ◽

Sea Ice Thickness ◽

Subjective Analysis ◽

Stage Of Development ◽

Volume Estimates ◽

The Impact

AbstractThis work evaluates two distinct calculations of central tendency for sea-ice thickness and quantifies the impact such calculations have on ice volume for the Southern Ocean. The first calculation, area-weighted average thickness, is computed from polygonal ice features and then upscaled to regions. The second calculation, integrated thickness, is a measure of the central value of thickness categories tracked across different scales and subsequently summed to chosen regions. Both methods yield the same result from one scale to the next, but subsequent scales develop diverging solutions when distributions are strongly non-Gaussian. Data for this evaluation are sea-ice stage-of-development records from US National Ice Center ice charts from 1995 to 1998, as proxy records of ice thickness. Results show regionally integrated thickness exceeds area-weighted average thickness by as much as 60% in summer with as few as five bins in thickness distribution. Year-round, the difference between the two calculations yields volume differences consistently >10%. The largest discrepancies arise due to bimodal distributions which are common in ice charts based on current subjective-analysis protocols. We recommend that integrated distribution be used for regional-scale sea-ice thickness and volume estimates from ice charts and encourage similar testing of other large-scale thickness data archives.

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