Matthew Garcia | University of Wisconsin-Madison (original) (raw)

Papers by Matthew Garcia

Poster presented at the University of Wisconsin, Nelson Institute, Center for Climate Research, 5... more Poster presented at the University of Wisconsin, Nelson Institute, Center for Climate Research, 50th Anniversary Celebration.

Agricultural and Forest Meteorology, 2022

Presented at poster session of the 2007 AGU Joint Assembly. Poster describes outline and scope of... more Presented at poster session of the 2007 AGU Joint Assembly. Poster describes outline and scope of disaggregation and downscaling methods for application of coarse precipitation field to high-resolution land surface models, and an assessment of method accuracy across various regions of the continental US.

Landsat has a history of use in the diagnosis of land surface phenology, vegetation disturbance, ... more Landsat has a history of use in the diagnosis of land surface phenology, vegetation disturbance, and their impacts on numerous forest biological processes. Studies have connected remote sensing-based phenology to surface climatological patterns, often using average temperatures and derived growing degree day accumulations. I present a detailed examination of remotely sensed forest phenology in the region of western Lake Superior, USA, based on a comprehensive climatological assessment and 1984-2013 Landsat imagery. I use this climatology to explain both the mean annual land surface phenological cycle and its interannual variability in temperate mixed forests. I assess long-term climatological means, trends, and interannual variability for the study period using available weather station data, focusing on numerous basic and derived climate indicators: seasonal and annual temperature and precipitation, the traditionally defined frost-free growing season, and a newly defined metric of ...

Remote Sensing of Environment, 2021

Abstract Mast seeding in conifers is characterized by the spatially synchronous and temporally va... more Abstract Mast seeding in conifers is characterized by the spatially synchronous and temporally variable production of seed cone crops. Large mast seeding events (known as “mast years”) can be a visually stunning and ecologically important phenomenon, supporting trophic interactions and survival of seed predators as well as forest regeneration. Documenting patterns in mast seeding is generally labor-intensive, requiring repeated visual cone counts at consistent and widespread locations over long periods to quantify the spatiotemporal variability of cone production. Our goal in this work was to evaluate the correspondence of multispectral vegetation indexes (VIs) from Landsat with ground-based observations of mast seeding in white spruce (Picea glauca) forests of the Kluane region, Yukon, Canada. Given the visual characteristics of mast seeding in white spruce, we tested: 1) whether photosynthesis- and color-oriented VIs can identify senescence of spruce cones in late summer and autumn during mast years, and 2) if moisture-oriented VIs can distinguish the significant drying of seed cones from the surrounding spruce canopy vegetation during that senescence and after seeds are released. We hypothesized that the slope of late season decline in VIs in spruce forests would be related to masting (i.e., greater decline in VI during mast years). Using generalized linear mixed-effects modeling (GLMM), we compared more than 100 site-year combinations of mast/non-mast observations to develop VI-based regressions. We found some success identifying mast years with moisture-oriented VIs, while models using the photosynthesis- and color-oriented VIs were not supported, given the data. However, we found that models containing multiple VIs from both categories were more successful than any single-VI model, accurately predicting four of sixteen mast events in site observations. We provide compelling evidence that mast-seeding patterns may be detectable using moisture-oriented Landsat observations over large coniferous forest areas. Additional work is warranted to distinguish the signal for mast events from confounding disturbance-related effects and to differentiate variation in VI signals attributable to masting productivity in contrast to effects of climatological variability on reflectance.

International Journal of Applied Earth Observation and Geoinformation, 2021

Abstract Repeat digital photography at or near ground-level is a proven and efficient approach fo... more Abstract Repeat digital photography at or near ground-level is a proven and efficient approach for tracking plant phenology. Here, we explored the potential to monitor phenology using the Snapshot Wisconsin (SW) trail camera network, a citizen science program. Using three curve-fitting methods for characterizing phenological transition dates, we assessed the phenological offset between understory vegetation and the overstory canopy in the trailcam observations and compared variations in derived phenology over the different spatial scales represented by trailcams (~20–50 m), Harmonized Landsat and Sentinel-2 (HLS, 30 m), and Moderate Resolution Imaging Spectroradiometer (MODIS, 500 m). Our results showed that the apparent phenological offset between understory and overstory vegetation differed among forest types: in broadleaf deciduous forests, understory vegetation had an earlier start-of-spring (SOS) and later end-of-autumn (EOA) than the overstory canopy; in mixed forests, the understory showed an earlier SOS than the overstory, but no significant difference in EOA; in evergreen conifer forests, neither SOS nor EOA differed significantly between the understory and overstory. We found moderate correlations (0.25 ≤ r ≤ 0.57) between trailcam- and satellite-derived phenological dates. Moreover, those derived dates varied significantly among the applied curve-fitting methods: total growing season length (from SOS to EOA) could be 19 days longer for a threshold-based method than for a logistic curve-fitting method (our reference model), but 17 days shorter than the logistic method when using a piecewise-continuous method based on fitted sine curves. Despite the spatial limitations of trailcams for characterizing phenology on landscape and regional scales, trailcam networks have considerable potential for informing local phenological studies and disentangling the many drivers of phenology that can remain undetected from the satellite perspective.

Journal of Advances in Modeling Earth Systems, 2014

Environmental Modelling & Software, 2007

Past studies have connected mean forest phenology from remote sensing analyses to regional climat... more Past studies have connected mean forest phenology from remote sensing analyses to regional climatological patterns, usually relying on long-term average temperatures and derived growing degree day accumulations. This long-term mean phenology is then used to inform land surface model vegetation dynamics in meteorological and climate modeling systems. We present a detailed, spatially-explicit examination of remotely sensed forest phenology in the region of western Lake Superior, USA, based on a comprehensive 1984-2013 climatological assessment [Garcia and Townsend, 2016] and Landsat imagery over the same period. The previous work showed that regional warming on land areas of 0.56°C during the 30-year study period contrasted with ~2.5°C warming in Lake Superior, one of the fastest-warming large lakes in the world, indicating possible long-term changes in land–lake interactions and hence vegetation phenology. As well, summer warming is accompanied by a regional precipitation decline of ...

Forests

We describe an individual-based model of spruce budworm moth migration founded on the premise tha... more We describe an individual-based model of spruce budworm moth migration founded on the premise that flight liftoff, altitude, and duration are constrained by the relationships between wing size, body weight, wingbeat frequency, and air temperature. We parameterized this model with observations from moths captured in traps or observed migrating under field conditions. We further documented the effects of prior defoliation on the size and weight (including fecundity) of migrating moths. Our simulations under idealized nocturnal conditions with a stable atmospheric boundary layer suggest that the ability of gravid female moths to migrate is conditional on the progression of egg-laying. The model also predicts that the altitude at which moths migrate varies with the temperature profile in the boundary layer and with time during the evening and night. Model results have implications for the degree to which long-distance dispersal by spruce budworm might influence population dynamics in lo...

Proceedings of the Wisconsin Space Conference, 2017

Flash flood events are a common hazard to life and property along the Colorado Front Range. The N... more Flash flood events are a common hazard to life and property along the Colorado Front Range. The National Weather Service (NWS) Glossary of Hydrologic Terms 1 specifies that a flash flood “follows within a few hours (usually less than 6 hours) of heavy or excessive rainfall.” The inherent difficulties in the forecasting and observation of heavy rainfall events in mountainous terrain only add to the problems of flash flood warning and damage mitigation. Such events may occur in this region under widely varied meteorological and ...

AGU Spring Meeting Abstracts, May 1, 2008

Collaborations between the Air Force Weather Agency (AFWA), the Hydrological Sciences Branch at N... more Collaborations between the Air Force Weather Agency (AFWA), the Hydrological Sciences Branch at NASA-GSFC, and the PRISM Group at Oregon State University have led to improvements in the processing of meteorological forcing inputs for the NASA-GSFC Land Information System (LIS; Kumar et al. 2006), a sophisticated framework for LSM operation and model coupling experiments. Efforts at AFWA toward the production of surface hydrometeorological products are currently in transition from the legacy Agricultural ...

A proper system of community preparation and warning leading up to a flood event is as important ... more A proper system of community preparation and warning leading up to a flood event is as important as preventing a disaster.

Remote Sensing of Environment, 2007

ABSTRACT The Arizona Hydrologic Information System (AHIS) is a web-based portal developed by the ... more ABSTRACT The Arizona Hydrologic Information System (AHIS) is a web-based portal developed by the Arizona Water Institute (AWI) and focused on developing better access, retrieval, and analytical capability for water-related data. To support this functionality, centralized access to numerous and distributed datasets from public and private sector interests and various academic sources are provided. AHIS provides for the service of meteorological, surface water, and subsurface hydrologic information such as groundwater well levels, withdrawals, and recharge measurements. AWI is affiliated with the three state universities in Arizona (ASU, NAU, and UA), with the state’s Departments of Water Resources (ADWR), Environmental Quality (ADEQ), and Commerce, and with numerous commercial and nongovernmental organizations. The AHIS project enhances communication between these and many other data providers, information consumers, and decision-makers. In cooperation with SAHRA at the University of Arizona (UA), AHIS provides for the correlation and combination of various water-related datasets including well withdrawal and recharge permits and surface water resources with the Arizona Wells database, which includes well water-level information provided by the ADWR, ADEQ, and USGS. Such wide collaboration provides an inherent requirement for information accessibility and data interoperability across subject disciplines, modeling systems, and decision-support tools. Data cataloging and dissemination are based on metadata standards and dataset markup languages for ease of use in modeling and visualization applications. These descriptions and classifications facilitate the discovery, collection, combination, and service of datasets and lead to their use in analyses and modeling studies for the development of derivative products, which provide scientists and decision-makers with a wealth of information focused on answering larger scientific and societal questions at hand.

AGU Spring Meeting Abstracts, May 1, 2006

We have evaluated three TRMM-based precipitation datasets against the ground-based Higgins gage d... more We have evaluated three TRMM-based precipitation datasets against the ground-based Higgins gage dataset (Higgins, et al., 2000) in Southeast US. The three TRMM-based datasets include 3B42RT, 3B42V6 (Huffman et al., 1995, 1997; Huffman, 1997), and CMORPH (Joyce, et al., 2004). We have performed temporal and spatial analysis on these products over the period from winter, 2002 to summer, 2005. Our timescale of analysis spans from seasonal to daily, and includes a case study of hurricane Jeanne, a 5-day ...