Modeling Surface Climate in US Cities Using Simple Biosphere Model Sib2

We combine Landsat- and the Moderate Resolution Imaging Spectroradiometer (MODIS)-based products in the Simple Biosphere model (SiB2) to assess the effects of urbanized land on the continental US (CONUS) surface climate. Using National Land Cover Database (NLCD) Impervious Surface Area (ISA), we define more than 300 urban settlements and their surrounding suburban and rural areas over the CONUS. The SiB2 modeled Gross Primary Production (GPP) over the CONUS of 7.10 PgC (1 PgC= 10(exp 15) grams of Carbon) is comparable to the MODIS improved GPP of 6.29 PgC. At state level, SiB2 GPP is highly correlated with MODIS GPP with a correlation coefficient of 0.94. An increasing horizontal GPP gradient is shown from the urban out to the rural area, with, on average, rural areas fixing 30% more GPP than urbans. Cities built in forested biomes have stronger UHI magnitude than those built in short vegetation with low biomass. Mediterranean climate cities have a stronger UHI in wet season than dry season. Our results also show that for urban areas built within forests, 39% of the precipitation is discharged as surface runoff during summer versus 23% in rural areas

Mapping Biophysical Parameters for Land Surface Modeling over the Continental US Using MODIS and Landsat

In terms of the space cities occupy, urbanization appears as a minor land transformation. However, it permanently modifies land's ecological functions, altering its carbon, energy, and water fluxes. It is therefore necessary to develop a land cover characterization at fine spatial and temporal scales to capture urbanization's effects on surface fluxes. We develop a series of biophysical vegetation parameters such as the fraction of photosynthetically active radiation, leaf area index, vegetation greenness fraction, and roughness length over the continental US using MODIS and Landsat products for 2001. A 13-class land cover map was developed at a climate modeling grid (CMG) merging the 500mMODIS land cover and the 30m impervious surface area from the National Land Cover Database. The landscape subgrid heterogeneity was preserved using fractions of each class from the 500 m and 30 m into the CMG. Biophysical parameters were computed using the 8-day composite Normalized Difference Vegetation Index produced by the North American Carbon Program. In addition to urban impact assessments, this dataset is useful for the computation of surface fluxes in land, vegetation, and urban models and is expected to be widely used in different land cover and land use change applications

Modeling The Urban Impact On Semiarid Surface Climate: A Case Study In Marrakesh, Morocco

We combine Landsat and MODIS data in the Simple Biosphere Model to assess the impact of urbanization on surface climate in a semiarid city in North Africa. The model simulates highest temperatures in urban class, with spring average maximum temperature differences to other land cover classes ranging between 1.6 C and 6.0 C. During summer, these maximum temperature differences are smallest (0.5 C) with barelands and highest (8.3 C) with irrigated lawns. This excess heating is simulated above and beyond a seasonal temperature average of about 30 C during spring and 44 C during summer. On annual mean, a full urbanization scenario decreases the carbon fixation by 0.13 MtC and increases the daytime mean surface temperature by 1.3 C. This may boost the city energy consumption by 5.72%. Under a 'smart growth' scenario, whereby the city expands on barelands to cover 50% of the study region and all remaining barelands converted to orchards, the carbon fixation is enhanced by 0.04 MtC with a small daytime temperature increase of 0.2 C. Our results indicate that vegetation can mitigate the urban heating. The hydrological cycle indicates that highest ratio of surface runoff to precipitation (43.8%) occurs in urban areas, versus only 16.7 % for all cover types combined

Impact of Urban Growth on Surface Climate: A Case Study in Oran, Algeria

We develop a land use map discriminating urban surfaces from other cover types over a semiarid region in North Africa and use it in a land surface model to assess the impact of urbanized land on surface energy, water and carbon balances. Unlike in temperate climates where urbanization creates a marked heat island effect, this effect is not strongly marked in semiarid regions. During summer, the urban class results in an additional warming of 1.45 C during daytime and 0.81 C at night compared to that simulated for needleleaf trees under similar climate conditions. Seasonal temperatures show urban areas warmer than their surrounding during summer and slightly cooler in winter. The hydrological cycle is practically "shut down" during summer and characterized by relatively large amount of runoff in winter. We estimate the annual amount of carbon uptake to 1.94 million metric tons with only 11.9% assimilated during the rainy season. However, if urbanization expands to reach 50% of the total area excluding forests, the annual total carbon uptake will decline by 35% and the July mean temperature would increase only 0.10 C, compared to current situation. In contrast, if urbanization expands to 50% of the total land excluding forests and croplands but all short vegetation is replaced by native broadleaf deciduous trees, the annual carbon uptake would increase 39% and the July mean temperature would decrease by 0.9 C, compared to current configuration. These results provide guidelines for urban planners and land use managers and indicate possibilities for mitigating the urban heat

Remote Sensing And Regional Climate Modeling Of Impacts Of Land Cover Changes On The Climate Of The Marmara Region Of Turkey

Tez (Doktora) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2008Thesis (PhD) -- İstanbul Technical University, Institute of Science and Technology, 2008Bu çalışmada, arazi örtüsünde meydana gelen değişimlerin Marmara Bölgesi yaz iklimi üzerindeki etkisi, Landsat görüntülerinin iklim modelleme için kullanılabilirliği ve iklim modellemede kullanılan arazi örtüsü verilerinin doğruluğu araştırılmıştır. Bu amaçla, 1975 ve 2005 yılları için Landsat uydu görüntüleri kullanılarak Marmara Bölgesi arazi örtüsü verileri oluşturulmuştur. 2005 yılı arazi örtüsü verisi, bölgesel iklim modellerinde kullanılan global arazi örtüsü verisi ile kıyaslanıp, model arazi örtüsü verisindeki eksiklikler tespit edilmiştir. 1975 ve 2005 yılı arazi örtüsü verileri Weather Research and Forecasting (WRF) modelleme sistemine girdi olarak sunulup, bu verilerle model çalıştırılmıştır. Ayrıca modelin içindeki arazi kullanımı verisi kullanılarak kontrol simülasyonu gerçekleştirilmiştir. 2005 arazi örtüsü verisi ile gerçekleştirilen simülasyon sonuçları, kontrol simülasyonundan daha iyi sonuç vermiştir. Arazi kullanımı verisinin kalitesinin arttırılması daha doğru iklim simülasyon sonuçlarının alınmasına yardımcı olmuştur. Ayrıca. 1975 ve 2005 yılı arazi kullanımı ile yapılan simülasyon sonuçları karşılaştırılıp, Marmara Bölgesinde meydana gelen arazi kullanımı değişimlerinin lokal iklim üzerindeki etkisi incelenmiştir. Karşılaştırmalar sonucunda, Marmara Bölgesinde özellikle şehirleşmenin arttığı İstanbul, Bursa ve Adapazarı illerinde yaz ayı minimum ve ortalama sıcaklıklarının arttığı, rüzgar doğrultu ve şiddetlerinin değiştiği gözlemlenmiştir. Model sonuçları, arazi örtüsü verileri ve diğer ilgili tüm veriler Coğrafi Bilgi Sisteminde ortak bir çatı altında toplanarak, arazi kullanımı değişiminin iklim üzerindeki etkisi detaylı bir şekilde incelenmiştir. Çalışma sonuçları, Landsat uydu görüntülerinden üretilen arazi örtüsü verilerinin bölgesel iklim modelleme de başarıyla kullanabileceği ve bu verilerle daha doğru iklim simülasyon sonuçlarının elde edilebileceği gösterilmiştir.In this research, investigation of land cover change impact on summer climate of the Marmara Region, utilization of Landsat images in regional climate modeling and assessment the accuracy of global land cover data sets used in were employed. Land cover data of 1975 and 2005 were produced using Landsat satellite images. 2005 land cover data was compared with global land cover data used in regional climate models and deficiencies and inaccuracies in model land cover were determined. 1975 and 2005 land cover data then implemented to Weather Research and Forecasting modeling system and two experiments were conducted with these data. Besides, a control run was employed using model land cover data. The experiment conducted with 2005 land cover gave better results then control experiment. Improving the land cover data improved the climate simulation results. Another comparison was made between the results of 1975 and 2005 land cover data runs to analyze the impact of land cover change on local climate of the region. Comparison results show that minimum and average temperatures increased and wind directions and magnitudes changed as a result of urbanization increase in the Marmara Region especially in İstanbul, Bursa and Adapazari. Climate model results, land cover data and other ancillary data were collected in a Geographic Information System to determine the impact of land cover change on climate in detail. The results of this study showed that land cover data produced from Landsat images can be successfully used in regional climate modeling and more accurate climate simulation results can be obtained with these improved data.DoktoraPh

Forest Management and Water Resources in the Anthropocene

Decades of research has provided a depth of understanding on the relationships among forests and water, and how these relationships change in response to climate variability, disturbance, and forest management. This understanding has facilitated a strong predictive capacity and the development of best management practices to protect water resources with active management. Despite this understanding, the rapid pace of changes in climate, disturbance regimes, invasive species, human population growth, and land use expected in the 21st century is likely to create substantial challenges for watershed management that may require new approaches, models, and best management practices. These challenges are likely to be complex and large scale, involving a combination of direct effects and indirect biophysical watershed responses, as well as socioeconomic impacts and feedbacks. We explore the complex relationships between forests and water in a rapidly changing environment, examine the trade-offs and conflicts between water and other resources, and examine new management approaches for sustaining water resources in the future

Modeling the impact of land surface feedbacks on post landfall tropical cyclones

The land surface is an important component of numerical models. The land surface models are modules that control energy partitioning, compute surface exchange coefficients and form the only physical boundary in a regional scale numerical model. Thus, an accurate representation of land surface is critical to compute surface fluxes, represent the boundary layer evolution and affect changes in weather systems. Land surface can affect landfalling tropical cyclones in two ways: (i) when the cyclone is offshore and land can influence cyclones by introducing dry (or moist) air that can weaken (or strengthen) the organized convective structure of cyclones, and (ii) land can affect the evolution of cyclones post landfall by modifying the surface heat fluxes and introducing additional surface drag. In this dissertation, the hypothesis that improved representation of land surface conditions will improve the prediction of landfalling tropical cyclones is tested. To that effect, a comprehensive review of land surface effects on tropical cyclones was undertaken and an idealized study was conducted to study the impact of antecedent soil temperature on the sustenance/reintensification of tropical cyclones over land. Rainfall verification for cyclone events over the Atlantic Ocean was conducted and a comparison study between land models—GFDL Slab and Noah, also considers the sensitivity of tropical cyclone models to land surface parameterizations. The recent adoption of Noah land model with hydrology products in HWRF offers a unique opportunity to couple a river routing model to HWRF to provide streamflow estimations from the HWRF model and this dissertation has outlined techniques to real time predict streamflow for United States with HWRF forcing. Results from this dissertation research indicate antecedent land surface conditions can affect tropical cyclone evolution post landfall and high soil temperature and thermally diffusive soil texture of land surface are critical factors contributing to re-intensification/ sustenance of tropical cyclones. This idealized study, in addition to enabling improved understanding of the land surface effects on cyclones, has also led to a developmental effort to incorporate landfalling capability in the idealized framework of HWRF model and is available for use for the wider tropical cyclone community. The development of river routing coupled HWRF model could also be used in the operational mode to improve flooding and streamflow predictions and efforts are underway to integrate this new capability in HWRF. Study findings contribute to the understanding regarding the effects of land surface on landfalling cyclones and helps translate research products into HWRF’s operational framework for predicting tropical cyclones

Land Ecosystems and Hydrology

The terrestrial biosphere is an integral component of the Earth Observing System (EOS) science objectives concerning climate change, hydrologic cycle change, and changes in terrestrial productivity. The fluxes o f CO2 and other greenhouse gases from the land surface influence the global circulation models directly, and changes in land cover change the land surface biophysical properties o f energy and mass exchange. Hydrologic cycle perturbations result from terrestrially-induced climate changes, and more directly from changes in land cover acting on surface hydrologic balances. Finally, both climate and hydrology jointly control biospheric productivity, the source o f food, fuel, and fiber for humankind. The role of the land system in each of these three topics is somewhat different, so this chapter is organized into the subtopics of Land-Climate, Land-Hydrology, and Land-Vegetation interactions (Figures 5.1, 5.2, and 5.3)