David Kuria

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Papers by David Kuria

Quantitative drought monitoring in a typical cold river basin over Tibetan Plateau: An integration of meteorological, agricultural and hydrological droughts

Journal of Hydrology, 2016

We introduce a Rainfall, Snow and Glacier melt (RSG) standardized anomaly (SA) index to reflect w... more We introduce a Rainfall, Snow and Glacier melt (RSG) standardized anomaly (SA) index to reflect water availability in cold river basins by taking into account snow and glacier melt that influence seasonal water availability. The study takes advantage of a high-resolution Water and Energy Budget-Based Hydrological Distributed Model with improved snow physics (WEB-DHM-S) at a grid size of 5 km to quantify hydrological regimes in a typical cold river basin in the Tibetan Plateau (Lhasa River basin as a demonstration site) from 1983 to 2012. Standardized anomaly index was utilized as drought Indicator whereby each meteo-hydrological parameter involved in drought quantification was fitted to a distribution pattern on a monthly basis. Akaike Information Criterion and Bayesian Information Criterion were used as selection criteria. Drought indices were computed from the model inputs and outputs, which included RSG for meteorological drought, soil moisture (surface and root-zone) for agricultural drought and discharge and groundwater level for hydrological drought. From spatial and temporal analyses,

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Small Water Enterprises in Africa 2: Kenya. A study of small water enterprises in Nairobi

For centuries, Small Water Enterprises (SWEs) have supplied a large share of the water market in ... more For centuries, Small Water Enterprises (SWEs) have supplied a large share of the water market in the urban centres of most low-income countries. Such SWEs have proved themselves economically viable, and often operate in competitive conditions. They extend water services to informal settlements that have little prospect of being supplied with piped water from the local utility. Unfortunately, they attract comparatively little investment, and even less support from governments. The incremental but critically important improvements they can provide tend to be overlooked by governments and international agencies. This book is one of a series of outputs from a project designed to identify and test out ways of improving the water services delivered to the urban poor through SWEs. Along with the other books in the series listed below, it will prove an invaluable resource for water utility managers and policymakers. How Small Water Enterprises can contribute to the Millennium Development Goals (including evidence from four African cities); Small Water Enterprises in Africa 1: Tanzania; Small Water Enterprises in Africa 2: Kenya; Small Water Enterprises in Africa 3: Sudan; Small Water Enterprises in Africa 4: Ghana.

A Radiative transfer Model for Soil Media with Considering the volume Effects of Soil Particles: field observation and Numerical Simulation

2006 IEEE International Symposium on Geoscience and Remote Sensing, 2006

Abstract This paper presents the development of an improved soil radiative transfer model (RTM) w... more Abstract This paper presents the development of an improved soil radiative transfer model (RTM) which considering the volume scattering effect of soil particles, an unexplored part of traditional RTMs, through field experiments and numerical simulations. The field observations were conducted by using the ground based passive microwave radiometer (GBMR) to measure the brightness temperature of dry sand layer over background materials, metal plates or absorbers. The existence of volume scattering effects in the dry ...

Land-Atmosphere Coupled Data Assimilation by AMSR-E

A flash flood control system based on the Global Earth Observation System of Systems (GEOSS/FFCS)

Satellite-based Atmosphere-land Coupled Data Assimilation System

Open source web mapping technologies: can developing countries leverage and tap the potential they portend?

Web-based GIS Approach to Enhance Public Participation in Development Planning: Developing The Emuhaya Constituency WebGIS Portal

This paper presents an approach taken in the implementation of a community webGIS portal. Local c... more This paper presents an approach taken in the implementation of a community webGIS portal. Local community empowerment and inclusion in resources planning and management were the key objectives of the project. A hybrid Y-Model methodology for webGIS development was adopted. The methodology splits up the development activities into two clear lines; the GIS development and Web development lines before integrating the two into a single product. The findings of the project indicate that disseminating information about the presence of a community webGIS will greatly influence its effectiveness. Community literacy levels also directly influence usability of the platform. Most users at the community level lack the expert technical competence it is therefore important to maintain simplicity in design and content presentation on the webGIS. The developed system leverages on web technologies to integrate data from disparate sources and make the same seamlessly available during the planning process.

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Development of a soil moisture retrieval algorithm for spaceborne passive microwave radiometers and its application to AMSR-E and SSM/I

2007 IEEE International Geoscience and Remote Sensing Symposium, 2007

Abstract This paper reports the development of a soil moisture retrieval algorithm for spaceborne... more Abstract This paper reports the development of a soil moisture retrieval algorithm for spaceborne passive microwave radiometers. The algorithm is based on a modified radiative transfer model, so-called DMRT-AIEM model. The implementation of this algorithm consists of three steps: 1) forward model parameters optimization; 2) lookup table generation and 3) lookup table reversion and soil moisture estimation. The algorithm was tested at a CEOP (coordinate enhanced observing period) reference site on the Mongolia Gobi. The ...

Moritoring Wingter Wheat Growth With Grand Based Microwave Radiometers (GBMR)

IGARSS 2008 - 2008 IEEE International Geoscience and Remote Sensing Symposium, 2008

Abstract From November 2006 to June 2007 a field experiment&amp;amp;amp;amp;#x27;Tanashi Expe... more Abstract From November 2006 to June 2007 a field experiment&amp;amp;amp;amp;#x27;Tanashi Experiment&amp;amp;amp;amp;#x27;was conducted in a farm of the University of Tokyo, Japan. Continuous ground measurements of meteorological variables, soil moisture and temperature profiles and vegetation status have been taken. At the same time, the ground based microwave radiometers (GBMR) are employed to provide accurate field measurements of brightness temperature up-welling from the plot, at the frequencies of 6.925, 10.65, 18.7, 23.8, 36.5 and 89 GHz. The scientific ...

Mapping groundwater potential in Kitui District, Kenya using geospatial technologies

International Journal of Water Resources and Environmental Engineering, 2012

Kitui district is a semi-arid region characterized by erratic and unreliable rainfall. Despite th... more Kitui district is a semi-arid region characterized by erratic and unreliable rainfall. Despite this, the main economic activity is rain-fed agriculture, with irrigation agriculture taking place on small parcels adjoining riparian reserves. During the dry season, local people travel long distances in search of water, necessitating groundwater potential mapping to support exploitation and complementing other water sources in the district. In this study geospatial technologies are used to identify and map groundwater potential zones using climate, geophysical and geological data. These datasets were appropriately weighted in a modified DRASTIC based overlay scheme. Land-cover data was derived from landsat imagery classification, with lineament density obtained from the same satellite products. A groundwater potential zones map was generated which showed that the central and eastern regions of Kitui district are the most suitable for groundwater exploitation. Existing water points (which were not considered in the study) are situated in this region, hence validating the study.

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Multi-Frequency Microwave Response to Periodic Rougheness

2006 IEEE International Symposium on Geoscience and Remote Sensing, 2006

Abstract A series of field experiments were conducted to verify the effects of roughness on passi... more Abstract A series of field experiments were conducted to verify the effects of roughness on passive microwave emission. From these field experiments, it was observed that surface roughness increases observed brightness temperatures (higher emissivity) at horizontal polarization while diminishing the vertically polarized brightness temperatures marginally. The advanced integral equation method (AIEM) and QP models were found to model the effects of surface roughness fairly reasonably. The QP model which is a parameterized ...

A Coupled Data Assimilation Framework utilizing multifrequency passive microwave remote sensing in retrieval of land surface variables and integrated atmospheric variables: development and application over the Tibetan Plateau

International Journal of Remote Sensing, 2012

Retrieval of land surface variables and atmospheric variables over land from passive microwave re... more Retrieval of land surface variables and atmospheric variables over land from passive microwave remote-sensing data sets has been a challenge for many years. A lot of progress has been made in these quests such as using cloud-resolving models and data assimilation. Data assimilation allows the integration of observations (including observation errors) into imperfect models, thereby yielding more improved model forecasts. In this work, a coupled data assimilation framework (CDAF) is proposed and applied to predict the evolution of land surface and atmospheric conditions. CDAF comprises a coupling of two data assimilation schemes, namely a land data assimilation scheme (LDAS) and an ice microphysics data assimilation scheme (IMDAS). This system has been developed and evaluated using data for the Tibetan Plateau. In this framework, both low-frequency and high-frequency passive microwave brightness temperatures (T B s) are assimilated. Low-frequency T B s are assimilated in the LDAS subsystem and used to obtain land surface conditions, which are subsequently used as improved initial conditions together with high-frequency T B s and assimilated in the IMDAS subsystem to obtain atmospheric conditions. The retrieved land surface variables and integrated atmospheric variables are demonstrated to show good agreement with observed land and atmosphere conditions such as those derived from point measurements of temperature and soil moisture (using the Soil Moisture and Temperature Measurement System (SMTMS)), sonde, Advanced Infrared Sounder (AIRS) and Global Precipitation Climatology Project (GPCP) products. The distribution of integrated cloud liquid water and cloud ice is shown to follow the observed cloud distribution over the study area. It is shown that by using IMDAS with modifications to account for precipitation and a good description of land surface emission, it is possible to obtain precipitation information of high fidelity over the land surface. Retrieved integrated water vapour using IMDAS shows correspondence with 'corrected' AIRS total precipitable water product. It is also shown that the relative humidity profile obtained from IMDAS agrees with the corresponding sonde profile. From the simulations, it is clear that by using the CDAF, there is marked improvement in the forecast conditions compared with the non-assimilation scenario for all of

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A coupled Land Atmosphere Radiative-Transfer Model (LA-RTM) for multi-frequency passive microwave remote sensing: development and application over Wakasa Bay and the Tibetan Plateau

International Journal of Remote Sensing, 2011

Multi-frequency passive microwave sensors herald a new dawn for combined land and atmosphere obse... more Multi-frequency passive microwave sensors herald a new dawn for combined land and atmosphere observations. Past efforts to utilize microwave remote sensing of atmosphere and land surface have proceeded by treating these two areas in a parallel fashion. In this research, a unified approach is presented that can be used to improve both quantitative and qualitative understanding of land and atmosphere constituents. A coupled Land Atmosphere Radiative-Transfer Model (LA-RTM) that can be used as a forward model in retrieval ...

Field-Supported Verification and Improvement of a Passive Microwave Surface Emission Model for Rough, Bare, and Wet Soil Surfaces by Incorporating Shadowing Effects

IEEE Transactions on Geoscience and Remote Sensing, 2007

To investigate the potential of passive microwave techniques for observing the atmosphere over la... more To investigate the potential of passive microwave techniques for observing the atmosphere over land, it is important to understand the nature of emissions from the land surface. The heterogeneity of large-scale land surface emissions has been cited as a major impediment in conducting observations of the atmosphere over land. Many models, both theoretical and empirical, have been developed to explain the surface emission with varying degrees of success. In the past, most field-supported research in soil observations using microwave techniques has concentrated on lower frequencies (L-band). This paper reports on a study, supported by field data, that seeks to improve our understanding of surface emission at various frequencies using passive microwave radiometers. This provides a crucial link between remote sensing of the land surface and the atmosphere. We show that it is important to consider shadowing associated with rough wet surfaces. By incorporating shadowing effects, the advanced integral equation model (AIEM) shows remarkable agreement with observations at all frequencies and polarizations. Although the roughness parameters obtained during our experiment correspond to very rough conditions, by including shadowing effects the AIEM model is able to transition from the not so rough natural condition as observed from space to the very rough as obtained during field experiments.

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Development of the Coupled Atmosphere and Land Data Assimilation System (CALDAS) and Its Application Over the Tibetan Plateau

IEEE Transactions on Geoscience and Remote Sensing, 2012

Land surface heterogeneities are important for accurate estimation of land-atmosphere interaction... more Land surface heterogeneities are important for accurate estimation of land-atmosphere interactions and their feedbacks on water and energy budgets. To physically introduce existing land surface heterogeneities into a mesoscale model, a land data assimilation system was coupled with a mesoscale model (LDAS-A) to assimilate low-frequency satellite microwave observations for soil moisture and the combined system was applied in the Tibetan Plateau. Though the assimilated soil moisture distribution showed high correlation with Advanced Microwave Scanning Radiometer on the Earth Observing System soil moisture retrievals, the assimilated land surface conditions suffered substantial errors and drifts owing to predicted model forcings (i.e., solar radiation and rainfall). To overcome this operational pitfall, the Coupled Land and Atmosphere Data Assimilation System (CALDAS) was developed by coupling the LDAS-A with a cloud microphysics data assimilation. CALDAS assimilated lower frequency microwave data to improve representation of land surface conditions, and merged them with higher frequency microwave data to improve the representation of atmospheric conditions over land surfaces. The simulation results showed that CALDAS effectively assimilated atmospheric information contained in higher frequency microwave data and significantly improved correlation of cloud distribution compared with satellite observation. CAL-DAS also improved biases in cloud conditions and associated rainfall events, which contaminated land surface conditions in LDAS-A. Improvements in predicted clouds resulted in better land surface model forcings (i.e., solar radiation and rainfall), which maintained assimilated surface conditions in accordance with observed conditions during the model forecast. Improvements in both atmospheric forcings and land surface conditions enhanced land-atmosphere interactions in the CALDAS model, as confirmed by radiosonde observations.

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Microwave Remote Sensing of Land Surface Status During a Long Term Experiment, and Its Application to Validate a Parameter Optimization Method

Journal of hydroscience and hydraulic engineering, May 1, 2009

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An Open Source GIS Solution for Managing Water Supply, Distribution and Billing

Setting up of a Kenya National Domestic Violence Call Center (K-NDVCC): Prototype and Pilot Implementation

International Transaction Journal of Engineering, Management, & Applied Sciences & Technologies, Jan 27, 2012

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Developing an adapted land administration domain model profile for Kenya

Land Use Policy, 2022

Land is an important resource globally and its administration and management are crucial in meeti... more Land is an important resource globally and its administration and management are crucial in meeting the Sustainable Development Goals (SDGs) for example goal 15 and targets 1.4, 2.3, and 5.a. Most land information, more so in the developing countries, are paper based and manually managed. Several countries are working on digital migration for land processes and administration. This is done by first developing a data model for both land parcel and attribute information. International Standards Organization (ISO) Land Administration Domain Model (LADM) was developed in 2012 as a universally accepted model for managing land information. Since then, several countries have developed their country profiles, while others are in the process of developing their regional or country profiles based on their unique requirements. In Kenya, work on a country profile is underway. Several factors need to be considered while developing or extending a LADM country profile. These include a defined scope and stakeholder involvement. Sound methodology is required to deliver a country model. Reviewing the existing legal framework and processes is key. Consequently, the needs of the users and reviewing the earlier proposed models is important. This research, has in addition, interviewed stakeholders and experts on land administration in Kenya and validated these through Focus Group Discussions. To meet requirements related to gender rights and recordation, community land rights, pastoralists seasonal occupation of land and informal occupation required special attention in the process of developing the model for Kenya. The required attributes, Rights, Restrictions and Responsibilities (RRR) and relationship between the classes were also identified. This paper provides a comprehensive set of requirements for developing an extended country profile for Kenya based on the ISO LADM.

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