Martti Hallikainen | Aalto University (original) (raw)

Papers by Martti Hallikainen

IEEE Journal of Oceanic Engineering, 1984

The meeting series is intended for specialists working with theoretical, experimental or applicat... more The meeting series is intended for specialists working with theoretical, experimental or application aspects of active and passive microwave remote sensing of the Earth, Oceans, Ice and Atmosphere. Microwave Signatures 2013 provides an international forum for reporting and discussing recent achievements in microwave remote sensing instrumentation, methodology, and applications. The meeting has attracted professionals from around the world and consists of a serial sequence of oral and poster sessions. We would like to thank all members of the International Steering Committee for their work for a successful symposium. Thanks are also due to the organizers of the invited sessions: GNSS Reflectometry, L-band Active/Passive Land Surface Retrievals and SMAP, and Microwave Propagation in Vegetated and Snow Covered Soils. We also wish to thank sponsors of the Symposium. Three Commissions of the International Union of Radio Science (URSI) support the Symposium: Commission F (mode B, including travel support) and Commissions B and E (mode A, technical support). Other sponsors include the Institute of Electrical and Electronics Engineers (IEEE) Geoscience and Remote Sensing Society (GRSS) (technical support), Aalto University, and the City of Espoo. We sincerely hope that you enjoy the Symposium and your stay in Finland.

Changes in permafrost and seasonally frozen ground extent on the Earth’s surface are indicators o... more Changes in permafrost and seasonally frozen ground extent on the Earth’s surface are indicators of climate change. Aalto university is d eveloping methods for large scale monitoring of frozen soil in the frequency range be tween 300 and 1000 MHz.

2011 IEEE International Geoscience and Remote Sensing Symposium, 2011

IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing

The estimation of chlorophyll-a (chl-a) concentration remains a great challenge in turbid waters ... more The estimation of chlorophyll-a (chl-a) concentration remains a great challenge in turbid waters due to their complex optical conditions. To improve chl-a estimation, this study aims to determine whether combined use of polarimetric synthetic-aperture radar (SAR) data has potential for improving the chl-a estimation from hyperspectral sensing reflectance for turbid waters such as those found in Lake Taihu, China. In situ measurements of hyperspectral reflectance data and water samples were collected over the lake corresponding to ENVISAT ASAR data. Semiempirical (two-band and three-band models) and empirical [multiple linear regression (MLR) and multilayer perceptron network (MLP)] models are compared to estimate the chl-a concentration from in situ hyperspectral reflectance and SAR data. The results show that there is a general underestimation of chl-a for concentrations higher than 26 ug/L, which is probably caused by the large spatial variation of chl-a in the study area. The results also demonstrate that the MLR model performs in a more stable manner than the MLP network does, while MLP underestimates low and high areas of chl-a concentrations in the lake. On the other hand, due to the availability of one scenic SAR data on the same day, our results show that the additional use of SAR data improved chl-a estimation very slightly in this case study, although the performance of vertical/vertical polarization SAR data was better than that of horizontal/horizontal polarization data in chl-a estimation. Potential

12th European Microwave Conference, 1982, 1982

Microwave dielectric measurements were made on snow samples with wetness between 0 and 0.12 by vo... more Microwave dielectric measurements were made on snow samples with wetness between 0 and 0.12 by volume and densities between 0.17 and 0.37 g/cm3 A free-space transmission method was used at eight frequencies between 4 GHz and 18 GHz. The data at each frequency have been fitted with a model that assumes a linear dependence on snow wetness. The average correlation

IEEE Geoscience and Remote Sensing Magazine

new chapter, which is warmly welcome in the GRSS community! This section also reports an updated ... more new chapter, which is warmly welcome in the GRSS community! This section also reports an updated table with all the active GRSS chapters. The Education column includes a report on the Remote Sensing "Summer" School 2013 held on July 18-19, 2013, in Melbourne, Australia, just before IGARSS 2013. The article provides a summary of the activities of this very successful school (which, considering its geographical location, was a Winter school rather than a Summer school). The Conference Reports section contains two contributions. The first is an article describing the GRSS Major Awards and Fellow Recognitions presented at the IGARSS 2013 Plenary Session held on July 22, 2013, in Melbourne, Australia. The article describes the excellent organization of IGARSS 2013 and provides information on all the Major

Physics and Chemistry of the Earth

IGARSS 2003. 2003 IEEE International Geoscience and Remote Sensing Symposium. Proceedings (IEEE Cat. No.03CH37477), 2000

In this paper an empirical algorithm for the estimation of the time of increased free liquid wate... more In this paper an empirical algorithm for the estimation of the time of increased free liquid water content in snowpack has been assembled and tested using SSM/I data. The algorithm is based on employment of the microwave radiometer channel differences together with the hydrological model-based estimated temperature of the target. The obtained results show that the progress of snow melt

IGARSS 2001. Scanning the Present and Resolving the Future. Proceedings. IEEE 2001 International Geoscience and Remote Sensing Symposium (Cat. No.01CH37217), 2000

ABSTRACT The behavior of the SSM/I-derived brightness temperature of snow-covered terrain vs. dry... more ABSTRACT The behavior of the SSM/I-derived brightness temperature of snow-covered terrain vs. dry snow water equivalent and land use is examined for the winters of 1996-97 and 1997-98 in Finland. The effect of several factors to the response is investigated. A method is proposed to correct the brightness temperature variation due to temperature changes

Proceedings of IGARSS '94 - 1994 IEEE International Geoscience and Remote Sensing Symposium, 2000

CAPABILITY OF RADAR AND MICROWAVE RADIOMETER TO CLASSIFY SNOW TYPES IN FORESTED AREAS Jarkko Kosk... more CAPABILITY OF RADAR AND MICROWAVE RADIOMETER TO CLASSIFY SNOW TYPES IN FORESTED AREAS Jarkko Koskinen, Lauri Kurvonen, Ville Jaaskeliiinen ... M. Hallikainen, J. Hyyppa, J. Haapanen, T. Tares, P. Ahola, J. Pulliainen and M. Toikka &quot;A helicopter-borne 8 ...

IGARSS 2003. 2003 IEEE International Geoscience and Remote Sensing Symposium. Proceedings (IEEE Cat. No.03CH37477), 2000

Dry snow temperature, snow water equivalent (SWE) and snow depth have been retrieved by using the... more Dry snow temperature, snow water equivalent (SWE) and snow depth have been retrieved by using the 19 and 37 GHz SSM/I brightness temperatures and Artificial Neural Networks (ANN's). The results obtained have been compared with those obtained using other approaches such as the Spectral Polarization Difference, the HUT Model-based iterative inversion, the Chang algorithm and linear regressions. In general, it has been noted that the ANN based technique gives better results than the other approaches, which tend to underestimate the unknown parameters.

IGARSS 2003. 2003 IEEE International Geoscience and Remote Sensing Symposium. Proceedings (IEEE Cat. No.03CH37477), 2000

A radar-based method for producing both land-cover classification and stem volume estimates for t... more A radar-based method for producing both land-cover classification and stem volume estimates for the forested areas is demonstrated. The method utilizes multi-temporal INSAR data that is segmented into quasi-homogenous segments, and a semi- empirical backscattering-coherence model that is inverted to produce stem volume estimates for the forest segments. Forest stands with known stem volumes are required as training areas for

IEEE International Geoscience and Remote Sensing Symposium, 2000

Presents the detection of sea surface temperature (SST) in the Gulf of Finland using AVHRR data. ... more Presents the detection of sea surface temperature (SST) in the Gulf of Finland using AVHRR data. AVHRR imagery is evaluated as a main data source for monitoring SST as a measure of upwelling dynamics. Sea surface effects (SSE), however, cause a temperature difference between the sea surface skin and water below the surface. Therefore, SSE are taken into account as one of the major error factors in the SST estimation.

2011 Ieee International Geoscience and Remote Sensing Symposium, Jul 1, 2011

IGARSS'97. 1997 IEEE International Geoscience and Remote Sensing Symposium Proceedings. Remote Sensing - A Scientific Vision for Sustainable Development, 1997

Sea ice is one of the most important components of the Earth's cryosphere. It modifies the sea-ai... more Sea ice is one of the most important components of the Earth's cryosphere. It modifies the sea-air heat and momentum exchanges, Earth's radiation budget and affects the global heat and freshwater circulation. None of the existing satellite instruments can provide detailed measurements of the sea ice topography and elevation, that is necessary for the study of the sea ice mass balance. This paper presents the results of an analysis that was made for the European Space Agency concerning the feasibility of a spaceborne laser altimeter for sea ice measurement. The analysis indicates that a laser altimeter with a spatial resolution of 50 m-100 m can be used to globally measure sea ice thickness and estimate sea ice mass with an accuracy exceeding the accuracy of the present spaceborne measurement techniques.

IGARSS 2003. 2003 IEEE International Geoscience and Remote Sensing Symposium. Proceedings (IEEE Cat. No.03CH37477), 2003

An L-band noise injection radiometer (NIR) has been designed and implemented by Helsinki Universi... more An L-band noise injection radiometer (NIR) has been designed and implemented by Helsinki University of Technology Laboratory of Space Technology for the SMOS (Soil Moisture and Ocean Salinity) mission of ESA [1]. The work is performed as a part of ESA's MIRAS Demonstrator Pilot Project-2 (MDPP-2) under a subcontract for EADS-CASA. Other partners in the MDPP-2 NIR project are Toikka Engineering Ltd. and Ylinen Electronics Ltd. NIR will work as a part of the MIRAS (Microwave Imaging Radiometer Using Aperture Synthesis) instrument. Its main purpose is (1) to provide precise measurement of the average brightness temperature scene for absolute calibration of the MIRAS image map and (2) to measure the noise temperature level of the internal active calibration source for individual receiver calibration. The performance of NIR is a decisive factor of the MIRAS performance. The challenge in the implemented, so-called blind correlation, method is the fact that there is additional noise in the correlated signal due to using the noise injection method. The main objective of this paper is to demonstrate the feasibility of this technique.