In the framework of EGS, using hydraulic stimulation increases pore pressure into the existing fracture networks and can be responsible for slip reactivations. In order to predict the seismic or aseismic character of these slips, it is important to determine the influence of the gouge characteristics on the slip behaviour. Lab or in-situ testing can be very helpful, but experience has shown that it is complicated to install local sensors inside a mechanical contact and that some data remains impossible to obtain. In this study, we are focusing on the physics of the contact inside a granular gouge to understand the mechanisms of slip triggering by using numerical modelling. We implement a 2D granular fault gouge with Discrete Element Modelling (DEM). The model involves two rough surfaces representing the rock walls separated by a granular gouge with realistic angular particles created by the wear of previous slips. A displacement-driven model with dry contact is primarily studied to observe the peak of static friction (shape, slope or duration). In order to spotlight the aseismic and seismic patterns, a second model is carried out to add the stiffness of the rocks (or loading apparatus). Dedicated post processing tools are also used in order to analyse the spatial distribution of the solid fraction and the force chains patterns bringing a new understanding of physics from a granular point of view. Representing realistic morphology of particles (angular shapes) brings an additional level of control with respect to most of the simulations reported in the literature using circular grains. Angular grains lead to higher friction coefficients with different global behaviours. The initial solid fraction of the gouge appears to be a good indicator of the friction peak we have at a slip triggering (Fig.). The more compacted the gouge is, the more effort is needed to disturb the initial grains assembly and to reach a steady state regime. With fractal size distribution, we have also studied the mechanical contribution of small particles in the media. Friction coefficient results let us conclude that the presence or not of very small particles is not as influent as the initial solid fraction of the gouge. Finally, adding a stiffness on the upper rock wall provides information on the transition from stable sliding to slow-slip/stick-slip behaviour.

The DNA molecules are stable but easily fragmented by ionization radiation, which challenges DNA integrity in searching for evidence for extraterrestrial life on icy satellites. The objective was to estimate the highest value of the attenuation effect of freezing temperature on the efficacy of gamma-radiation in fragmenting dsDNA. A bacterial 16S rRNA gene inserted in a vector as a lyophilized crude cell lysate was irradiated (60Co) under the liquid nitrogen conditions (-195.8oC). The outcome was tested in a specific PCR, generating the MAIN (~600bp) as well as EXTRA “mis-primed” small-sized (~70bp) amplicons. At the ambient temperature, the main PCR product entirely disappeared upon the doze 7.5kGy while at -195.8oC, it withstood ~750kGy (~100 times difference). Vise-verse, the EXTRA short amplicon reached the maximum outcome at the dose ~400kGy and continued to persist until the tested dose 840kGy. By extrapolation, the given product could be generated upon irradiating target DNA at a dose of more than 1mGy. Such a find opens a chance (and time window of more than 25 years) to pick up freshly flushed out sub-ice-ocean microbes/DNA and get frozen as inclusions in water matrices on the Jovian Europa to verify the extraterrestrial life.

Maar-diatremes are inverted conical structures formed by subterranean excavation and remobilization of country rocks during explosive volcanism and common in mafic volcanic fields. We focus on impacts of excavation and filling of maar-diatremes on the local state of stress, and its subsequent influence on underlying feeder dikes, which are critical for understanding the development of intrusive networks that feed surface eruptions. We address this issue using finite element models in COMSOL Multiphysics®. Inverted conical structures of varying sizes are excavated in a gravitationally loaded elastic half-space, and then progressively filled with volcaniclastic material, resulting in changes in the orientations and magnitudes of stresses generated within surrounding rocks and within the filling portion of the maar-diatreme. Our results show that rapid unloading during maar-diatreme excavation generates a horizontal compressive stress state beneath diatremes. These stresses allow magma to divert laterally as saucer-shaped sills and circumferential dikes at varying depths in the shallow feeder system, and produce intrusion geometries consistent with both field observations from exhumed volcanic fields and conceptual models of diatreme growth. Stresses generated in these models also provide an explanation for the evolving locations of fragmentation zones over the course of diatreme’s filling. In particular, results from this study suggest that: (1) extensional stresses at the base of the diatreme fill favor magma ascent in the lower half of the structure, and possibly promote volatile exsolution and magma fragmentation; and (2) increased filling of diatremes creates a shallow compressive stress state that can inhibit magma ascent to the surface, promoting widespread intra-diatreme explosions, efficient mixing of host rock, and upward widening of the diatreme structure.

Isolating significant signals from temporal variations in autotrophic and heterotrophic components of ecosystem respiration (Reco) is required to better quantify the temperature sensitivity of the land carbon cycle processes. Here we present diurnal and seasonal patterns in field and model-based components of respiration and investigate their responses to environmental conditions at a dry eucalypt forest, the Cumberland Plain SuperSite of the Australian Terrestrial Ecosystem Research Network. We conducted measurement campaigns of total CO2 flux from the soil surface (Rsoil), soil microbial respiration (Rmicrobe), root respiration (Rroot), litter respiration (Rlitter), and stem respiration (Rstem) in 2018. In total, six infrared gas analyzers with closed, dynamic auto-chambers and six forced diffusion auto-chambers were used for periodic campaigns. Further, Reco and its components were simulated using the Community Atmosphere-Biosphere Land Exchange model (CABLE), constrained by eddy covariance measurements and chamber measurements of Rsoil. A new version of CABLE was implemented with the Dual Arrhenius Michaelis Menten (DAMM) formulation to assess the importance of substrate availability for simulating Rmicrobe. We found that respiration rates showed similar diurnal patterns among the components, showing diurnal hysteresis between respiration components and temperature. In this dry ecosystem, the respiratory components were more responsive to seasonally increasing temperature in wet than in dry periods, and the responses were dependent on atmospheric relative humidity affecting the litter layer moisture content. The temperature sensitivity was significantly higher in Rstem than in other components. Based on observed fluxes of Rmicrobe in trenched plots and Rsoil in intact soil plots, the mean contribution of Rroot to Rsoil was less than 20 % for the dry seasons, while mean Rstem was two times greater than mean Rsoil suggesting that Rstem should be not overlooked in ecosystem flux estimations. This study highlights that partitioning the respiratory components and accounting for their different temperature-responses will be necessary to reduce uncertainty in modelling carbon-climate feedbacks.

Canary Islands constitute an active volcanic archipelago. From the time immediately before the Castilian conquest of the islands, 17 volcanic eruptions have occurred: 2 prehispanic and 15 historical, some of them with multiple eruptive vents, affecting the islands of Lanzarote, Tenerife, La Palma and El Hierro. In order to carry out the inventory of geosites for the Canary Islands at a regional scale, it has been applied a methodology consisting of two sequential phases: the first one address the selection of geosites that will be part of the inventory, and the second one deals with the characterization and assessment of the selected geosites. In this methodology, geosites are selected within geological frameworks previously established given their regional significance for Canary Islands. With this aim, 12 geological frameworks representative of the geodiversity of Canary Islands have been identified, which include the essential elements, processes and morphologies of the Canarian geology, covering all stages of construction of the islands as well their geological evolution, including processes, morphologies, fossils and deposits associated both to the volcanism and the external geological agents. The selection of geosites is then constrained and facilitated by its representativeness within each geological framework. One of these 12 geological frameworks corresponds to “Historical and prehistorical volcanism”. The scarce number of volcanic eruptions, their low frequency and their general characteristics –fissure mafic eruptions, low VEI and strombolian eruptive styles- determine an apparent geological homogeneity. Nevertheless, the high variety of processes, morphologies and deposits associated to this framework, their good conservation status, as well as the information from the historical chronicles, have permitted to identify 19 geosites of high scientific value. They highlight the existence of eruptive styles ranging from hawaian to vulcanian, with short phases of water-magma contact, quiet emissions of water or in geysers, phreatomagmatic explosions, etc. These geosites constitute a unique and representative record of the volcanology, geomorphology, tectonics and petrology characterizing the most recent mafic volcanism of the Canarian archipelago.

Historically, location algorithms have relied on simple, one-dimensional (1D, with depth) velocity models for fast, seismic event locations. The speed of these 1D models made them the preferred type of velocity model for operational needs, mainly due to computational requirements. Higher-dimensional (2D-3D) seismic velocity models are becoming more readily available from the scientific community and can provide significantly more accurate event locations over 1D models. The computational requirements of these higher-dimensional models tend to make their operational use prohibitive. The benefit of a 1D model is that it is generally used as travel-time lookup tables, one for each seismic phase, with travel-time predictions pre-calculated for event distance and depth. This simple, lookup structure makes the travel-time computation extremely fast. Comparing location accuracy for 2D and 3D seismic velocity models tends to be problematic because each model is usually determined using different inversion parameters and ray-tracing algorithms. Attempting to use a different ray-tracing algorithm than used to develop a model almost always results in poor travel-time prediction compared to the algorithm used when developing the model. We will demonstrate that using an open-source framework (GeoTess, www.sandia.gov/geotess) that can easily store 3D travel-time data can overcome the ray-tracing algorithm hurdle because the lookup tables (one for each station and phase) can be generated using the exact ray-tracing algorithm that is preferred for a specified model. The lookup surfaces are generally applied as corrections to a simple 1D model and also include variations in event depth, as opposed to legacy source-specific station corrections (SSSCs), as well as estimates of path-specific travel-time uncertainty. Having a common travel-time framework used for a location algorithm allows individual 2D and 3D velocity models to be compared in a fair, consistent manner.

Since 1990s, dramatic land-use changes have occurred across mainland China. Large areas of cereal lands have been converted into horticultural crops because of lucrative economic benefits. Fruits and vegetables together in China have consumed more than 30% of N fertilizers. Therefore, understanding the long-term effects of land use change from cereals to orchard on N budgets in croplands at the county scale over long-term is very important for managing N in agricultural systems in China. We selected three Counties (Luochuan (LC), Mixian (MX), and Wugong (WG)) on the Loess Plateau with different land-use changes since 1990s in Shaanxi to compare the changes of N budgets in croplands at the county scales. The main crops in the three Counties were cereals (wheat and corn) before 1990s. After 1990s, the land uses in LC and MX changed dramatically; and LC and MX become the main apple and kiwifruit production county in China, respectively. The main crops in WG are still wheat and corn. It provides an ideal reference to compare the effects of land use changes on N budgets in croplands at the county scale. The N inputs and outputs, N surplus and N use efficiency (NUE, computed as N in harvested crop products divided by N inputs) at the three Counties from 1990 to 2017 were quantified. The annual N inputs and N surplus of the three Counties since 1990s were increased, and NUE decreased significantly. Compared to WG, the annual N input and N surplus of cropland of LC and MX were very high, and NUE was very low. For example, NUE in LC decreased from 64% in 1990 to 12% in 2017; and NUE in WG decreased from 55% in 1992 to 38% in 2017. To understand the fate of surplus N in cropland of LC, we also collected soil profile samples (0-6 m) from cereal lands and apple orchards in different sites of the county. The average nitrate accumulation in 0–6 m soil profiles reached 5611 kg N/ha in 2017. Approximately 67% of the total N surpluses in LC from 1990 to 2017 was accumulated in soil profile as nitrate. Land use change from cereals to orchard result in high surplus N in croplands at the county scale. The nitrate accumulation in the vadose zone is the main fate of surplus N in the intensive agricultural landscape, which should be considered an important component of the soil N budget to optimize production and environmental protection.

In the last 20 years, there has been an international effort to develop approaches to experimentally measure the petrophysical and geomechanical properties of hydrate-bearing core samples. The measurements are extremely challenging because sub-sampling, sample preparation, and testing must be conducted at high pressure and low temperature. Despite these challenges, multiple laboratories are now measuring the geotechnical properties of hydrate-bearing sediments. However, there have been relatively few attempts to validate these measurements. We developed experimental protocols to accurately conduct zero-lateral strain tests at effective stresses up to 20 MPa using a pressure core triaxial device. We directly measure displacement during compression through periodic instantaneous undrained loading. To evaluate the accuracy of our measurement system, we conducted a benchmark study to compare properties obtained in our pressure core test chamber against classical geotechnical devices. We prepared a Boston Blue Clay specimen through re-sedimentation. Comprehensive properties databases favor the use of this material for comparison analyses. A compression test to 20 MPa accurately reproduced the compression, lateral stress, and permeability behavior demonstrated in previous testing programs. This experimental procedure provides a convenient framework for future validation studies in a broad range of pressure core laboratory devices.

The left-lateral Enriquillo-Plantain Garden Fault (EPGF) is one of two transform systems that define the Northern Caribbean plate boundary zone. Relative motion across its trace (~ 10 mm/yr) evolves from nearly pure strike-slip in western Haiti to transpressional in eastern Haiti, where the fault system may terminate against a south-dipping oblique reverse fault. Lake Azuei is a large (10 km x 25 km) and shallow (< 30 m deep) lake that lies in the direct extension of the EPGF in eastern Haiti. A single core previously collected in the lake suggests high sedimentation rates at its depocenter (~6 mm/yr). The shallow lake stratigraphy is therefore expected to faithfully record any tectonic deformation that occurred within the past few thousand years. In January 2017, we acquired a grid of high-resolution (~10 cm), shallow penetration (~4 to 5 m) subbottom seismic (CHIRP) profiles spaced 1.2 km apart across the entire lake. A new bathymetric map compiled from these CHIRP data and some prior echosounder survey reveals a flat lake floor (<0.01°) surrounded by steep (~5°) shoreline slopes. The CHIRP profiles highlight several gentle folds that protrude from the flat lakebed near the southern shore, an area where transpressional deformation is presumably focused. Thin (< 20 cm) horizontal strata from the lakebed can be traced onto the flanks of these gentle folds and pinch out in an upward curve. They also often pinch upward onto the base of the shoreline slopes, indicating that young sediments on the lakebed bypassed the folds as well as the shoreline slopes. We interpret this feature as diagnostic of sediments deposited by turbidity currents. The fact that young turbidites pinch out in upward curves suggests that the folds are actively growing, and that active contractional structures (folds and/or blind thrust faults) control much of the periphery of the lake. A few sediment cores were strategically located where beds are pinching out in order to maximize stratigraphic records. Two of these cores successfully penetrated strata imaged by the CHIRP profiles. On-going Pb210 dating of sediment samples from the cores should constrain sedimentation rates and thus help quantify the rates of the tectonic deformation.

High altitude platforms (HAPs) such as stratospheric balloons and eventually other high altitude, long endurance unmanned vehicles have reached a stage where it is possible to deploy a persistent fleet of aircraft acting as a meteorological observation network for a reasonable cost. Whether directly collecting in situ measurements like winds aloft or via dropsondes or performing remote sensing using, for example, radar or GPS radio occultation, these observation networks can collect measurements which are hard to obtain from other observation platforms and are complementary to other systems. They are also highly autonomous and can be deployed worldwide (and thus can add redundancy to the global forecast system). Because they are mobile, the observation network can be adjusted to collect in situ measurements in the places that are most important to forecasters and scientists. We use simulation of fleets of stratospheric balloons that are navigated by machine learning algorithms that actuate an altitude control system to demonstrate some of the potential constellations that are achievable with HAPs and motivate the greater consideration of an autonomous, persistent HAPs-based meteorological observing network.

Using Electron Backscattered Diffraction (EBSD), we conducted a preliminary study on 6 core samples from the San Andreas Fault Observatory at Depth (SAFOD) between 3193-3311m Measured Depth. The selected samples represent areas of the fault zone in contact with the actively creeping Central Deforming Zone (CDZ) and Southwestern Deforming zone (SDZ), with one sample from within the CDZ. The samples were selected on the basis of containing significant pyrite, and evidence of multiphase calcite-vein-formation from cathodoluminescence (CL) imaging. EBSD results identify primary pyrite in the form of framboids, pyrite-cemented framboid aggregates and spherulitic pyrite overgrowths. Secondary (hydrothermal) pyrite forms a 15x7mm lenticular mass in one sample and records abundant evidence of core-and-mantle subgrain-rotation (SGR) deformation mechanisms in pyrite (Fig. 1), indicating elevated temperatures >400° C. We find a second generation of both plastically deformed and undeformed secondary pyrite that overgrows calcite-filled fractures in boudinaged Dauphiné-twinned-quartz clasts. Undeformed second-phase pyrite is also associated in the main secondary pyrite mass with calcite filled extension-fractures kinematically compatible with extension fractures in boudinaged quartz. Low-T pyrite cataclasis is also evident. Multiple generations of e-twinned calcite veins are revealed by CL (Fig. 1). The twin-density paleo-piezometry suggests differential stresses of 25-233 MPa, consistent with previous estimates and with the present-day temperature at the SAFOD. However, EBSD also reveals abundant evidence for dislocation-creep in calcite, commonly including the youngest veins in the samples. While dislocation creep deformation is possible in calcite at SAFOD depth, it would involve very high CRSS. Pyrite clearly records multiple episodes of formation and deformation during decreasing T from >400° C to present SAFOD conditions. Analysis of the deformation microstructures in this study also suggests a similar P-T history for calcite and quartz. Preliminary interpretation of the results in this study are: 1. SAFOD damage zone rocks close to SDZ and CDZ deformed, at least episodically, while being exhumed and 2: The deformation involved neo-mineralization and fluid overpressure events.

My laboratory is developing an accelerometer. However, if you do not install the dedicated software, you can not browse the data. In addition, since it is necessary to go to the site on a semi-annual basis and collect data due to capacity problems, the current operation is burdened. In order to solve these problems, we devised WebGL that enables high-speed drawing when processing a large amount of data such as Big Data, and a Web application that uses server that can transmit, save, and download acquired data. In this application, an accelerometer and a raspberry pie are connected, and the raspberry pie receives data obtained from the accelerometer and sends the data to a server installed in a laboratory by SCP file transfer at regular intervals. These data specify the location and date from the client side through the Internet browser, download the data using the download function of the browser, read this data on the application and draw the waveform. The data obtained from the accelerometer in the development to date is converted into a CSV file and transferred to the server. These data can be downloaded and displayed on the web application. For the google map displayed on the right side of the screen, it is to make the application more useful by registering the location where the accelerometer was set in the future.

Every river and its bed has a flourishing life thriving environment. Search of life in these region will help us to find out if really life existed in Mars. Commonly life could be of any form based on the surrounding environment. Artificial Intelligence could help us to find what kind of organisms could have existed based on the minerals found in the Jezero Crater site. In this research we deep learning with the list of elements found at site and conclude to what kind of creature sediments to search for. This could make our search easier to look for sediments. The basic idea of this research to bring out what to search for based on the environment in and around the Jezero Crater.

The retroarc of the North American Cordilleran orogen in Nevada and Utah has been divided into the frontal Sevier fold-thrust belt in Utah, which accommodated shortening between ~145 and ~50 Ma, and a broad region of Nevada referred to as the ‘Sevier hinterland’. The hinterland is hypothesized to have developed into a high-elevation orogenic plateau (or ‘Nevadaplano’) at some point between the Late Jurassic and the Paleogene. Recent paleoaltimetry utilizing clumped isotope temperature estimates suggests that at least some basins on the Nevadaplano were at an elevation of 2.2-3.1 km by the latest Cretaceous. However, it remains uncertain precisely when the Nevadaplano attained these high elevations and if surface uplift developed steadily along with protracted shortening in the Sevier fold-thrust belt or occurred rapidly and was decoupled from the shortening record. In order to extend the surface elevation history of the Nevadaplano further back in time, we have investigated the type-exposure of the mid-Cretaceous (~113-98 Ma) Newark Canyon Formation (Knc) in central Nevada. The Knc records synorogenic sedimentation in the Sevier hinterland during the early to middle stages of shortening in the Sevier thrust belt. We will present terrestrial surface temperature estimates from clumped isotope analyses derived from palustrine, lacustrine, and pedogenic carbonate-bearing facies. Contextualized by structural evidence and corrected for secular climate change, these data suggest that the studied Knc basin had not developed substantial surface elevation by the mid-Cretaceous. However, there was likely some considerable surface relief in this region associated with active fold-thrust structures in the upper crust. Preliminary temperature estimates range between 22 and 70°C. These temperatures reflect a range of facies-specific differences in primary carbonate formation, as well as, diagenetic overprinting of some samples. Consistently warm temperatures throughout the stratigraphic section suggest that there was no significant cooling due to elevation gain between ~113 and ~98 Ma. We will discuss the implications of these results for the style and timing of deformation and surface uplift within the Nevadaplano.

The agricultural sector is a major consumer of water for irrigation purposes. Precise quantification of irrigation water requirements will help in achieving sustainable water management. Root water uptake (RWU) is driven by transpiration demand exerted by crops and is influenced by factors such as weather and leaf area index (LAI). The root water uptake at a particular depth in the root zone depends on the local moisture content, soil type, and root density. Under certain conditions, lack of availability of soil moisture at a certain depth may be compensated by more water being drawn into the roots from wetter portions of the soil. To incorporate this mechanism, this study presents a compensated root water uptake model (CRWU) with application to maize crops grown in Indian climatic conditions. Irrigation field experiments were conducted at seven field plots with the same soil by adjusting the irrigation supplied to simulate different degrees of water stress. Daily soil moisture data recorded at different depths in the root zone, crop yield and biomass data help in assessing model performance and identifying a critical water stress index that governs the extent of compensation in RWU.

The Campi Flegrei caldera is well known for being one of the most volcanically risky areas in the world. Notably, it has an extension of about 120 square km, and 40% of its area is submerged forming the Gulf of Pozzuoli. A remarkable expression of the local volcanic dynamics is the slow ground displacement across the whole caldera. This peculiarity makes this area a natural laboratory for developing and testing innovative methods to assess seafloor deformation. Until 2008 no seafloor deformation measurements were performed in the submarine part of the caldera, while ground deformation measurements have been extensively and routinely acquired on land since the beginning of the last century. In 2008 CUMAS, a multisensor prototype buoy, was deployed in the Gulf of Pozzuoli within a program of extension of the land-based geophysical monitoring network toward the marine sector of the caldera. CUMAS, placed at 2.5 km from the coast in about 100 m water depth, was able to acquire the first sea floor deformation measurement in the submerged portion of the caldera. In 2016, a new marine monitoring network, MEDUSA, was deployed to achieve a larger coverage of the Gulf of Pozzuoli incorporating CUMAS. MEDUSA marine network presently consists of four instrumented buoys hosting geodetic GPS receivers on the top. Moreover, each buoy is connected through a cable to a seafloor module equipped with oceanographic and geophysical sensors including a bottom pressure recorder (BPR). One of the buoys is also equipped with a tide gauge. Using the GPS, BPR and tide gauge data provided by MEDUSA, we were able to assess the seafloor deformation field in the Gulf of Pozzuoli for the first time: we estimated a seafloor vertical displacement of about 10 cm ±1 cm over a period of twenty months embracing 2016 to 2018. The presentation is aimed at giving details about the design of MEDUSA and about the multiparameter data analysis leading to the deformation field estimation.

Horizontally-extensive lightning flashes occur frequently in association with mature and late phases of multicellular thunderstorms, both in trailing stratiform regions and horizontally-extensive anvils. The spatial relationship between these flashes and the parent cloud volume is of importance for space launch operational decision making, and is of broader scientific interest. Before this question can be accurately addressed, there is a need to understand the degree to which current lightning observation systems can depict the spatial extent of these long flashes. In this ongoing work, we will intercompare the depiction of horizontally-extensive flashes using several ground-based lightning locating systems (LLSs) located at Kennedy Space Center (KSC) with space-based observations observed by the recently-launched Geostationary Lightning Mapper (GLM) onboard the GOES-16 satellite. Ground-based datasets include the KSC Lightning Mapping Array (KSCLMA), the operational narrowband digital interferometer network MERLIN, and the combined cloud-to-ground and cloud lightning dataset produced by the U.S. National Lightning Detection Network (NLDN). The KSCLMA system is a network of VHF time-of-arrival sensors that preferentially report breakdown processes, and MERLIN is a network of VHF interferometers that point to the discharges in the horizontal plane. Observations to date indicate that MERLIN and the KSCSLMA provide similar overall descriptions of the spatial and temporal extent of these flashes, while the NLDN does not provide adequate spatial mapping of these flashes. The KSC LMA system has much better location accuracy, and provides excellent 3-dimensional representation within ~100 km of KSC. It also has sufficient sensitivity to provide 2-dimensional flash mapping within ~250 km of KSC. The MERLIN system provides a more-detailed representation of fast leader propagation (in 2 dimensions) with ~100 km of KSC. Earlier work during the CHUVA campaign in Brazil with similar systems and the (orbital) Lightning Imaging System (LIS) has shown that the interferometric data correlated much better in space and time with the LIS optical observations. We are currently investigating this relationship at KSC, where both the LMA and interferometer perform much better than the systems used during CHUVA.

The work of Monin and Obukhov has enabled a description of turbulent processes in the Atmospheric Boundary Layer using flux-variance similarity functions. These functions, also called Integral Turbulence Characteristics (ITC), are used to characterize the state of turbulence at all frequencies. However, due to the non-universality of ITC models, more investigations are necessary, especially in tropical regions where low wind conditions frequently occur. This study aims at investigating whether these normalized standard deviations obey the Monin-Obukhov Similarity Theory (MOST) above a forest site in the Sudanian climate, and at identifying the appropriate ITC models for this ecosystem. Data were collected from a 18m tower equipped with an Eddy Covariance system, above the clear forest at Bellefoungou’s village, Northwest of Benin, West Africa. The turbulence intensity parameters calculated for five years and half, were analyzed according to wind speed, stability conditions and seasons. From their relationships with the stability parameter, data driven models were then obtained by the nonlinear least squares. The results showed that, all similarity functions follow MOST with a 1/3 power law whatever the stratification of the atmosphere during all the seasons excepted the temperature which had a parabolic shape in near neutral condition (-0.05 < ζ < 0.1). A seasonal dependence of all ITCs was evidenced under stable conditions. Indeed, roughness length and strong winds which dominating especially in the dry season favored more efficient turbulent exchange at the site. We also showed that the heat transfer is relatively more efficient than H2O transfer under both stability conditions. The established temperature and CO2 similarity models are found to be closer, and for some given stratification conditions, to those already existing in literature. But a noteworthy finding is that the models often used to assign a quality criterion to turbulent fluxes showed an overestimation relatively to those established ‘locally’ for u and w through all atmospheric stratification.