People: Julien Brun and Ana P. Barros

Project description:

Tropical cyclones (TCs) are well known for hazardous aspects due to the damage and loss of life they cause along their track. Beyond this common association, hurricanes and tropical cyclones provide an important amount of freshwater to the landscape in a short time period. This significant input of freshwater is necessary for the recharge of surface and subsurface reservoirs for several regions of the world.

Recently, a debate emerged in the scientific community about the impact that climate change could have on TCs in term of path, frequency and strength of these events; some studies suggest a probable poleward propagation of the subtropics in response to warming in the troposphere. Independently of this debate, the goal of our study is to investigate the mid- and long-term impacts of major hurricanes on our landscape and the recovery processes of the environment in their aftermath. It will allow us to better understand what could be the impact on the water cycle of the exposed areas in case of changes in the location, frequency and/or strength of these phenomena. We focus on the major tropical cyclones (H1 to H5 on Saffir-Simpson scale) coming from the Atlantic basin and making their landfall in the southeastern part of the United States. Our research hypothesis is based on the fact that this area is already under periodic severe drought conditions (2000, 2001 and 2007); therefore, a change in water input combined with population growth could distort the natural water cycle by creating a water balance deficit and undermine the regional resiliency to extreme events. To this end, it is imperative to better analyze the role of these events in environmental sustainability.

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This figure shows the persistence of the vegetation disturbances during the following year of the hurricane Katrina with respect to USGS hydrological units (gauged basins). Note the impacts along the tracks of hurricanes Frances and Jeanne in 2004 (dot-dashed lines) such as in the Apalachicola River (in white).

Project Description:

 The Barros research group has installed a research-grade precipitation monitoring network in the Pigeon River Basin (PRB) in Western North Carolina. One meteorological tower and 32 rain gauges are currently deployed at high-elevation locations along ridgelines. In addition to collecting data from these instruments, which have been in the field for as long as three years, the group has conducted several Intensive Observation Periods (IOPs), at Purchase Knob, a central location along the Cataloochee Ridge in the PRB. These IOPs focused on the vertical structure and spatial variability of moderate and light rainfall in the inner mountain region. For example, in summer 2008 the IOP included the coordinated deployment of radiosondes, a tethersonde system, and microphysical characterization using disdrometers, high-speed camera and radar observations.

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The image above shows our network in purple circles (NASA PMM). It includes all other hydrological data sources in the region that we are able to use in our research. Note the contrast in gauge locations in the existing network compared with our new gauges: the new gauges are installed at high elevations on N-S ridges across the Appalachian range in the W-E direction, thus providing a unique perspective on storm systems coming from any direction as well as isolated activity developing locally in the inner mountain region.

Research Team: Julien Brun, Prabhakar Shrestha and Ana P. Barros

Project description:

MODIS satellite images show that the Himalayas act as a barrier for the aerosols being transported from the Indian Gangetic Plains (IGP). This accumulation of aerosols during the pre-monsoon season not only affects the radiation budget, but can also have a profound impact on the evolution of orographically induced clouds and the local hydrological cycle.

The coarse spatial resolution (10km*10km to reduce signal noise ratio) of MODIS aerosol products cannot resolve the effects of local terrain in the spatial organization of the aerosol plumes, which is critical for the study of aerosol-cloud rainfall interactions in this region. However, high resolution images from MODIS visible channels have the ability to show the organization of the aerosol plumes in the Plains that penetrate along north-south river valleys from the IGP to the Tibetan Plateau. The developed methodology aims to use MODIS visible channels to monitor the time-space evolution of aerosol intrusions in the Himalayas by applying object oriented classification algorithms and GIS techniques on the MODIS visible channels to extract the aerosols extent evolution along seasons during the MODIS era (2000 - 2009). This 3-D spatial information of aerosol extent at high spatial resolution could be used in numerous applications ranging from designing of field campaigns, aerosol transport modeling, and environmental health-impact studies.

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This figure displays the elevation extracted for each external object with the shaded relief of the area as background overlaid by contour lines every 500m. These first results show that the haze elevation and intrusion length varie from valley to valley, likely reflecting the wind patterns and terrain complexity. As expected, the farther into the mountain range, the higher the haze ceiling (up to 4,000 m) as the valley bottom elevation is increasing along the river valley." title="This figure displays the elevation extracted for each external object with the shaded relief of the area as background overlaid by contour lines every 500m. These first results show that the haze elevation and intrusion length varie from valley to valley, likely reflecting the wind patterns and terrain complexity. As expected, the farther into the mountain range, the higher the haze ceiling (up to 4,000 m) as the valley bottom elevation is increasing along the river valley.

NASA GPM-GV
Integrated Precipitation and Hydrology Experiment 2014

Ground validation (GV) campaigns before and after the launch of NASA’s Global
Precipitation Measurement Mission (GPM) Core satellite in early 2014 have been
planned to collect targeted observations to support precipitation retrieval algorithm
development, to improve the science of precipitation processes, and to demonstrate the
utility of GPM data for operational hydrology and water resources applications. The
Integrated Precipitation and Hydrology Experiment (IPHEx) centered in the Southern
Appalachians and spanning into the Piedmont and Coastal Plain regions of North
Carolina seeks to characterize warm season orographic precipitation regimes, and the
relationship between precipitation regimes and hydrologic processes in regions of
complex terrain.

Since 2007, a high elevation tipping bucket rain gauge network has been in place in the
Pigeon River Basin (PRB) in the Southern Appalachians and intensive observing periods
(IOPs) have been conducted in this and surrounding river basins to characterize ridgeridge
and ridge-valley variability of precipitation using radiosondes, tethersondes, Micro-
Rain Radars (MRRs), automatic weather stations and optical disdrometers. Important
results from these analyses include the importance of light (<3 mm/hr) rainfall as a
baseline freshwater input to the region especially in the cold season, and the high
frequency of heavy rainfall and severe weather in the warm season, and illuminate the
significant spatio-temporal variability of rainfall in this region.

IPHEX will consist of two activities: 1) an extended observing period (EOP) from
October 2013 through October 2014 including a science-grade raingauge network of 60
stations, half of which will be equipped with multiple raingauge platforms, in addition to
the fixed regional observing system; a disdrometer network consisting of twenty separate
clusters; and two mobile profiling facilities including MRRs; and 2) an intense observing
period (IOP) from May–July of 2014 post GPM launch focusing on 4D mapping of
precipitation structure during which NASA’s NPOL S-band scanning dual-polarization
radar, the dual-frequency Ka-Ku, dual polarimetric, Doppler radar (D3R), four additional
MRRs, and two X-band radars (NOAA NOXP, and X-Pol) will be deployed in addition
to the long-term fixed instrumentation. During the IOP, the NASA ER-2 and the UND
Citation aircraft will be used to conduct high altitude and “in the column” measurements.

The ER-2 will be equipped with multi-frequency-radiometers (AMPR and CoSMIR), the
dual-frequency Ka-Ku band, HIWRAP Ka-Ku band, CRS W-band, and EXRAD X-band
radars. The ER-2 instrument complement collectively functions as an expanded GPM
Core “satellite proxy”. The UND Citation instruments will be dedicated to microphysical
characterization. The ground-based instrumentation sites were selected to collect
extensive samples of orographic effects on microphysical properties of precipitation,
specifically DSDs, for the dominant warm season precipitation regimes in the region: 1)
westerly systems including Mesoscale Convective Systems (MCSs) and fronts; 2)
southerly and southeasterly convective systems and tropical storms; and 3) convection
initiation and suppression and feeder-seeder interactions among fog and multilayered
clouds in the inner mountain region. A real-time hydrologic forecasting testbed is
planned to be operational during the IPHEX IOP. In preparation for the forecasting
testbed, a benchmark project for intercomparion of hydrologic models has been
developed (H4SE) in the context of which all data necessary (GIS, atmospheric forcing,
land-surface attributes, soil properties, etc) to implement and operate hydrologic models
in four major SE river basins (the Savannah, the Catawba-Sandee, the Yadkin-Peedee and
the Upper Tennessee) were analyzed and processed at hourly time-step and at 1 km2
resolution over a 5-year period (2007-2012). Data are currently available from
http://iphex.pratt.duke.edu to all participants. The goal of H4SE is to facilitate
implementation of hydrologic models in the IPHEX region to assess the use and improve
the utility of satellite-based Quantitative Precipitation Estimates (QPE) for hydrologic
applications.

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Figure 1 - Extended IPHEx domain (EID) with focal SE river basins delineated. In
clockwise direction: Upper Tennessee (purple, 56,573 km²), Yadkin-Peedee (pink,
46,310 km²), Catwaba-Santee (blue, 39,862 km²), and Savannah (green, 27,110 km²).
The yellow rectangle denotes the Core Observing Area (COA) where ground validation
efforst will be concentrated.

Process studies integrating ground validation observations, satellite products and models in the Southern Appalachians

Ground-based observations of the vertical structure and horizontal variability of orographic precipitation in the Great Smoky Mountains exhibit strong spatial gradients and large variability at the diurnal, monthly, seasonal and inter-annual time-scales. Isolated thunderstorms generate up to 15% of the warm season rainfall (June-July-August-September), and as much as 30% of annual rainfall in less than 24 hours in the case of tropical cyclones. The serial propagation of shallow convective systems ahead of westerly fronts can produce up to 50% of all warm season rainfall in a matter of days such as during the SE floods of September 2009. Nevertheless, with exception of late afternoon and nighttime convective activity in the summertime, light rainfall dominates at all times of the day and increases from east to west.  Indeed, the contribution and frequency of light rainfall (intensity lower than 3 mm/hr) is on the order 60% to 70% in the winter and 30 to 50% in the summertime, which corresponds to about 50-60% of total annual precipitation, and up to 80% during drought (e.g. 2007-2008).  Light rainfall plays therefore a governing role in the regional water cycle with critical implications for water resources and ecosystem services in the Southern Appalachians.

More broadly, recent evidence suggests this is also the case elsewhere, especially where low level cloud systems interact with orographically forced clouds and fog such as the foothills of the Himalayas and the cloud forests and inner ridge-valley regions of the American Cordillera. Evaluation of the TRMM PR (TMPA V6) products in the Great Smoky Mountains showed that nearly 90% of missed events correspond to low rainfall rates (< 10 mm/hr).  For detected events, the error estimates range from 25 to100%, with larger errors (> 50%) for heavy rainfall.  The overarching science goal of the proposed category 2 research is to improve our understanding of orographic precipitation regimes and their relationship to hydrologic extremes leading to measurable advances in satellite remote-sensing of precipitation in mountainous regions. The specific research objectives are as follows: 1) to characterize the dynamics of light rainfall and shallow convection processes in the Southern Appalachians toward improving the representation of warm season orographic precipitation microphysics in models and satellite-based rainfall estimates; 2) to elucidate the relationship between orographic precipitation regimes, including snowfall, and the spatial and temporal variability of surface precipitation toward improving QPE (Quantitative Precipitation Estimation) and QPF (Quantitative Precipitation Forecasting), and ultimately the predictability of floods and associated biogeophysical hazards in mountain catchments; 3) to develop parameterizations of the thermodynamic and radiative effects of orographic low level clouds and fog on surface energy fluxes toward improving the predictive skill of hydrologic models at diurnal and seasonal scales in regions of complex topography; and 4) ground-validation and downscaling of satellite precipitation products in the Southern Appalachians through development of science-grade observations and ancillary data sets at high spatial and temporal resolution. 

The research approach includes maintaining a science-grade orographic precipitation observing system in the Southern Appalachians, developing precipitation downscaling models conditional on orographic precipitation regimes, and process studies through data analysis and the integration of atmospheric and hydrologic models and ground-based observations and satellite products.   The study is centered in the Southern Appalachians, but the research findings are relevant for mid-latitude mountains generally, and intermediate elevations (< 4,000 m) of tropical and subtropical mountain ranges. All data and models are available to the PMM community.

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This summarizes the laboratory experiments using current 5 RF sensors. During the second year, reliability testing of 5 RF sensors was conducted using 20 dB attenuators. Next, a second set of experiments was designed to simulate the snowpack under laboratory conditions. For this purpose, SWE was simulated as a depth of liquid water in Regicell Foam layers with different depths an different porosities. Results from this system level test were presented at the 2007 Fall Meeting of the American Geophysical Union in San Francisco, CA in December 2007.

Currently, we are working on developing the algorithm to extract amplitude change and phase shift as a function of time. The challenge is to quantity the phase shift accurately given that to keep the sensor costs down, the sensors to not have a reference clock. After quantifying the phase shift and amplitude, the complex permittivity of a variety of simulated “snowpacks” corresponding to varying liquid water depths, and foam thickness and porosity combinations will be characterized in the lab before going to actual field work with the snow sensor. I plan to perform field work in the upcoming 2008-2009 winter season in Finland via the GPM GV agreement and in the US.

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Mountain basins and the headwaters of river basins along the foothills of major mountain ranges are undergoing rapid environmental change due to urban development, land acquisition by private and public investors, demographic expansion, and climate change. The classical water infrastructure in these regions, if it is even present, is usually primarily designed to meet water supply and irrigation needs only.  Besides increased water demand, other impacts of anthropogenic land-use change are the shrinking of groundwater recharge areas, removal of vegetation, and the alteration of links between the landscape and the natural hydraulic system. Plus, regional climate change can affect the gross water balance due to changes in precipitation and evapotranspiration. Climate-hydrology-ecosystem feedbacks can in turn significantly change regional land-cover. The challenge toward sustainable and reliable water allocation policies is to preserve a functioning landscape that reflects key bio-physical hydro-connections (eco-hydrological sustainability) while meeting the basic water demands of natural and infrastructure systems.   

This research addresses the question of whether this challenge can be addressed by factoring the opportunity costs of environmental constraints, and economic value of conservation strategies into hydro economic assessments of water allocation policy at the basin level.  The research objectives are two-fold: 1) to develop an eco-hydrological meta-model for use in systematic economic analysis of water resources (soil moisture, groundwater, stream, vegetation), including their interactions and space-time variability; and 2) to characterize the contribution of \changes in water balance due to eco-hydrologic feedbacks of LULC (Land Use and Land Cover) and climate change to the economics of alternative adaptation strategies (land-conversion and water allocation policies).   Specifically, an exiting spatially–distributed eco-hydrological model with coupled surface-groundwater and vegetation dynamics will be integrated with an existing water allocation model in the context of a probabilistic hydro-economic framework.  This meta-model will be used to investigate water system behavior with respect to three state variables: a) extent of land-conversion (LC) defined in terms of LULC ; b) eco-hydrological sustainability (ES) defined in terms of  hydrological and ecological flows; and c) net present value (NPV), for baseline conditions (current climate, status-quo policy), and for alternative adaptation pathways under possible scenarios of future climate change.  

An innovated integrated meta-model and knowledge base framework for two-way feedback analysis between natural and urban systems will be developed to investigate adaptation strategies using water valuation metrics produced through systematic simulation procedures. The modeling framework will be tested and evaluated for the French Broad River in the Southern Appalachians, a representative case-study of mountain basins undergoing strong development pressures, in close collaboration with the Land-of-Sky Regional Council of natural resource managers. The research addresses national climate adaptation priorities to enable resilient communities, and is readily transferable to regions elsewhere undergoing large environmental change. The team expertise intersects Hydrology and Climate (Barros), Social Sciences and Water Resource Economics (Jeuland), Water Governance and Policy (Holman), Political Science and Econometrics (De Marchi), and Operations Research and Complex System Analysis (Trivedi), and two graduate students with interdisciplinary educational goals

People: Jing Tao and Ana P. Barros

Project description:

The dramatic growth of population in Africa since the 1950s has substantially accelerated water demand among nations, especially in Southern Africa where freshwater is extremely valuable and vulnerable. The Northern Kalahari Aquifer (NKA) system, the second largest aquifer basin in Southern Africa (Figure 1), underlies the southern-facing slopes of the Angola High Plateau (AHP), and is located between the rich Congo Intracratonic Basin to the north and the deep Southeast Kalahari Aquifer system to the south. Indeed, most of the headwaters of major rivers in Southern Africa including the Okavango and the Zambezi Rivers are located on the AHP, which provides a large amount of water recharge to the underling aquifer systems. The AHP is dominated by woodland savanna and tropical montane forests and grasslands, a complex transitional ecosystem between the Congo tropical rainforest and the Kalahari Desert. The Zambezi River is the fourth-largest river in Africa, which cuts across the subcontinent to discharge in the Indian Ocean. The Upper Zambezi River Basin (UZRB), separated from the lower part by Victoria Falls, provides essential freshwater resources to land-locked arid and semi-arid regions in between (Figure 1), and is the major recharge area to the NKA, demonstrating vigorous surface-ground water interactions in the region(shown by Figure 2). Despite its critical role in providing substantial water recharge to the NKA which provides most of the local freshwater resources, the hydroecology of the UZRB and its role in the regional water cycle have not been investigated previously by comprehensive hydrological modelling. This vacancy is attributed to the limitation of the accuracy of forcing datasets and the availability of ancillary data to support appropriate physical representation of hydrological processes, since there are virtually no ground-based hydrologic or hydrometeorological measurements to support modeling activities and much less predictive studies in the UZRB. Nevertheless, combining satellite data with proficient hydrological models fosters a promising solution to address science needs in this region. For example, the terrestrial water storage anomaly (TWSA) observations by NASA’s Gravity Recovery and Climate Experiment (GRACE) satellite provide a unique opportunity to evaluate and constrain basin-scale hydrologic models at large spatial scales. The time series of the UZRB basin-averaged GRACE TWSA demonstrates an obviously increasing trend during the last decade from 2003 to 2012 (Figure 3). Furthermore, through Data Assimilation techniques to optimally merge satellite observations and hydrological models, there is an opportunity to investigate hydrological processes and to develop a quantitative understanding of the regional water cycle in what is arguably the most critical river basin in Southern Africa. For this purpose, we will develop a Hydrologic Data Assimilation System (HDAS) which relies on a three-dimensional coupled surface-groundwater hydrology model (3D-LSHM) (Figure 4) integrated with an EnKF-based (Ensemble Kalman Filter) and/or EnKS-based (Ensemble Kalman Smoother) data-assimilation system (Figure 5), to characterize the seasonal (wet/dry) and inter-annual variability of the water budget of the UZRB and the NKA at high temporal-spatial resolution. The modeling system will subsequently be used in prognostic mode to assess the impact of land-use and land-cover (LULC) and climate change scenarios on water resource availability in the Upper Zambezi.

The overarching goal of the proposed research is to characterize regional water budget and water cycle at least for a ten-year period and to assess the vulnerability of water resources in Southern Africa, illustrated by the study in the UZRN and the NKA. In particular, the proposal has three specific science objectives: 1) to advance understanding of the spatio-temporal variability of surface-groundwater interactions in the region, and to characterize the regional water budget change in the terrestrial system and the subcomponents of the terrestrial system(e.g. surface water, soil water storage, and aquifer water storage) at both the seasonal and inter-annual time-scales; 2) to investigate the impacts of ongoing rapid land-cover-land-use (LCLU) change caused by both anthropogenic and non-anthropogenic factors (e.g. deforestation for agriculture, urbanization, mineral exploitation and wildfire) on the regional water cycle and vulnerability of water resources; and 3) to evaluate and predict how the availability of regional freshwater resources will respond to climate change in the following decades. The research hypothesis is four-fold: i) the vigorous surface-subsurface water interaction along the regional drainage network is very important for the long term sustainability of aquifers; ii) landform modulates soil-vegetation-atmosphere interactions in the AHP along altitudinal and latitudinal gradients, causing remarkable vegetation gradients which dynamically affect the soil and aquifer water storage at seasonal cycle; iii) the LCLU changes on the AHP and in the UZRB can alter dramatically the water cycle and overall water resource availability in the region; iv) the freshwater resources in Southern Africa are highly vulnerable and sensitive to external driving factors or disturbances, such as climate change and LULC change. 

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Figure 1: a) Angola High Plateau (AHP) plays an important role in partitioning water resources from precipitation among key major basins in the Southern Africa, and is a critical recharge area for the Northern Kalahari Aquifer (NKA) system. b) shows the large major aquifer systems in Africa. The NKA is between the rich Congo Intracratonic Basin and the deep Southeast Kalahari Aquifer system. c) illustrates the location of the Upper Zambezi River Basin (UZRB) while displaying the major river basins in Southern Africa. d) shows the digital elevation model(DEM) of the UZRB, also displaying the river systems of the area.

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Figure 2: Surface-Groundwater interaction is vigorous and highly nonlinear, showing large inter- and intra- variability, but staying active all year along in the floodplain.

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Figure 3: The time series of GRACE terrestrial water storage anomaly (TWSA) observations averaged over the UZRB area; the corresponding rainfall time series calculated from TRMM 3B42 product is also shown with the y-axis on the right.

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Figure 4: The schematic diagram of the 3D Land surface hydrologic model (3D-LSHM), displaying the one-dimensional soil column, two dimensional cross section and the three dimensional structure.

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Figure 5: The flowchart of the Hydrologic Data Assimilation System (HDAS), illustrated by the example of assimilating GRACE monthly TWSA data into the coupled surface-groundwater flow model (3D-LSHM).

The objective of this project is to investigate whether and how landform and landcover modulate the spatial and temporal variability of orographic clouds and precipitation in a high priority area for biodiversity conservation and human water supply. The central research hypothesis is that evapotranspiration is a critical source of moisture to the atmospheric boundary layer (ABL) either locally and, or remotely via moist transport by diurnal mountain-valley circulations, lowering the cloud base at high elevations during the afternoon, and enhancing thermodynamic instability at locations in the landscape where precipitable water and CAPE (Convective Available Potential Energy) attain collocated night-time maxima. Spatial patterns in the organization of convective initiation are proposed to be explained by the spatial variability of vegetation and soil moisture patterns on altitudinal gradients, and by how this translates into the spatial variability of the diurnal cycle of latent heating fluxes between the land surface and the lower troposphere.

Specifically, the following science questions are being addressed: (1) What is the contribution of evapotranspiration to the diurnal cycle of the energy budget of the lower troposphere in tropical mountainous regions?  How does it vary spatially with elevation and landform (ridges versus valleys, windward versus leeward slopes, foothills versus high peaks)?  (2) How does transversal (lateral) mountain variability in the spatial arrangement of landform and vegetation affect the diurnal cycle of convective activity and precipitation during the monsoon? (3) What is the relationship between the observed multi-scaling behavior of cloud fields from satellite imagery and the dominant spatial scales of convective activity associated with topography and, or land-use/land-cover patterns? (4) How can the current trends of land-use/land-cover change, and in particular deforestation and extension of agricultural activity to the highlands, change the water cycle in tropical mountainous regions?  What are the consequences of these changes for the long-term sustainability of tropical mountain ecosystems and water resources?

Five major activities have been carried out. Hypothesis testing, evaluation and validation of methodologies were conducted for US case-studies when data were not available in the region of study that could be used for this purpose. The methodologies are then transferred to the project's region of study.  

1) Field Observations  -  A network of hydrometeorological towers including above canopy measurements was installed and is being maintained  in the Kospiñata river valley, a tributary  of the Madre De Dios and Madeira rivers in the Amazon basin, in the Central Andes, Peru. The network spans roughly 4,000m on the envelope orography of Manu National Park.

2) Physical Modeling of Land-Atmosphere Interactions - Extensive modeling work with the WRF-ARW model has been carried out in order to use the model at very high resolution (~.2 km) over the very steep terrain of the Andes both at weather and climate time-scales, including ensemble simulations.  In preparation for this work the first simulations of the propagation of a hurricane (tropical storm) after landfall over the SE US and over complex terrain were conducted as a means to develop modeling skills and test and understand the model physics and numerics. For the Andes simulations, specific modeling research was required including addressing boundary layer processes from the representation of forest canopy to the parameterization of aerodynamic roughness, parameterization of convection, and developing physically-based framework to tracks land-atmosphere interactions at sub-second scale to isolate evapotranspiration feedbacks on atmospheric moisture processes from other sources and sinks of atmospheric moisture and energy. Half a million hours of NCAR supercomputer time was used to complete the model simulations, and about 100 Tb of data were generated by the model simulations.

3) Physical-Statistical Modeling of Climate-Landscape Evolution Feedbacks - Development of a statistical-physical model to link modern climate forcing to erosion rates in the Andes;

4) Scaling Analysis of Orographic Convection - Investigation of dynamical physical-statistical downscaling techniques, specifically focusing on the scaling behavior or cloudiness and precipitation under different convection regimes;

5) Diurnal Cycle Dynamics - Characterization of Diurnal Cycle Dynamics focusing on: 1) remote and local controls on atmospheric stability; and 2) the deep convection gap above 3,000 m on the eastern slopes of the Andes.  These studies are conducted using model results from activity (2), satellite data analysis, and nonlinear metrics.

Specific objectives related to each one of the major activities are as follows:

1) Characterize the diurnal, seasonal and  inter-annual variability of orographic precipitation processes on the Eastern Andes slopes that serve as the headwaters of the Amazon  basin;

2) Characterize the diurnal cycle of land-atmosphere interactions from the tropical forest up to the cloud forest in the headwaters of the Amazon basin for the dominant hydrometeorological regimes in the monsoon and dry seasons;

3) Characterize quantitatively the relationship between precipitation and material fluxes from the Eastern Andes to the Amazon foreland;

4) Characterize the dynamic scaling of orographic convection and develop a downscaling framework to enable high spatial resolution climate simulations on the eastern Andes and elsewhere over complex terrain.

5) Explain the dynamical underpinnings of the diurnal cycles of clouds and precipitation in the eastern slopes of the Andes toward elucidating the feedbacks between topography, ecohydrology, and climate.