Introduction

Data products from the Land Processes Distributed Active Archive Center (LP DAAC) are used in many different applications to serve as modelling tools, to illustrate and detect changes in landscape, and to assess variables of ecosystems, among others. Examples of these data applications can be found in the published literature. Below are highlights from some recently published articles, which feature data that are archived at the LP DAAC, and a more exhaustive list is available on the LP DAAC Publications page.

Mapping Disease Risk in Kansas

This study uses Moderate Resolution Imaging Spectroradiometer (MODIS) data to analyze the spatial and temporal patterns of a tick-borne disease and its relationship to environmental variables.

Science Objectives

MODIS data was used to track the spatial and temporal patterns of the Human Monocytic Ehrlichiosis (HME) infection in Kansas, USA from 2005 to 2012. The HME infection is caused by the Ehrlichia chaffeenisis bacterium carried by the Lone Star tick and infects humans through its bite. Symptoms of the infection can range from mild to fatal; HME has been a reportable disease in Kansas since 2000. The authors were seeking to understand the relationship of when and where infections were occurring to environmental, climatic, and socio-economic variables.

Instruments Used

MODIS land surface temperature (LST) and Normalized Vegetation Index (NDVI) data were used as climate variables in the modelling process.

Major Findings

The study found that the prevalence of HME has spread in a northwesterly progression across the state of Kansas for the years 2005 to 2012 and that occurrence is affected by environmental, climatic, and socio-economic variables. The study also identified previously unknown risk factors for HME.

References

Publication Reference

Raghavan, R.K., Neises, D., Goodin, D.G., Andresen, D.A., and Ganta, R.R., 2014, Bayesian spatio-temporal analysis and geospatial risk factors of human monocytic ehrlichiosis: PLoS ONE, v. 9, no. 7. doi:10.1371/journal.pone.0100850

Image Reference

Raghavan et al., 2014, CC BY 4.0

Measuring Water Stress in West Africa

MODIS LST and albedo data were used to evaluate evaporative fraction as an indicator of moisture conditions across a semi-arid African region.

Science Objectives

Daily evapotranspiration (ET) can be estimated by using the evaporative fraction (EF), which is the ratio of latent heat to available energy at the Earth’s surface. This study assessed a 2.9 km² area of Niger and Chad in Africa, spanning the Sahara Desert, the Sahel, and the Sudanian savanna, over a 10-year period (2000–2009). The aim of the study was to determine the EF of the study area and evaluate it as an indicator of moisture conditions.

Instruments Used

To calculate the EF, two MODIS products were used: MCD43B3, a 16-day albedo product, produced every 8 days, with 1-kilometer spatial resolution and MOD11A2, an 8-day land surface temperature product with 1-kilometer spatial resolution. Other satellite-derived data included rainfall estimates, vegetation and land cover, and dry matter productivity.

Major Findings

The results of this study showed that EF values could be derived for the study area using low-resolution satellite data, and are an indicator of moisture conditions for status monitoring of savannah ecosystems in the western African Sahel.

References

Publication Reference

Nutini, F., Boschetti, M., Candiani, G., Bocchi, S., and Brivio, P.A., 2014, Evaporative Fraction as an Indicator of Moisture Condition and Water Stress Status in Semi-Arid Rangeland Ecosystems: Remote Sensing, v. 6, no. 7, p. 6300–6323. doi:10.3390/rs6076300

Tracking Greenness Trends in Alaska

This study analyzed MODIS Enhanced Vegetation Index (EVI) data to evaluate long-term vegetation productivity changes in Alaska’s eastern boreal ecosystems.

Science Objectives

MODIS Enhanced Vegetation Index (EVI) data values from MOD13C2, a monthly vegetation index product with 5,600-meter resolution, were used as one component of a vegetation productivity study in Alaska. The author totaled the monthly EVI values for the growing season (May to September) from 2000 to 2010.

Instruments Used

The study used MODIS Enhanced Vegetation Index (EVI) data values from MOD13C2. 

Major Findings

This study concluded that over the 11-year study period, warming temperatures have led to an increase in growth rates of both shrubland and tundra vegetation in the eastern boreal zone of interior Alaska.

References

Publication Reference

Potter, C., 2014, Regional analysis of MODIS satellite greenness trends for ecosystems of interior Alaska: GIScience and Remote Sensing, v. 51, no. 4, p. 390–402. doi:10.1080/15481603.2014.933606