Monitoring NDVI of North Korea using NOSS AVHRR data
exploring the possibility of early warning system of agricultural production
Yoshide Sekimoto, Hiroaki Kndo and Ryosuke Shibasaki
Institute of Industrial Science, University of Tokyo
7-22-1, Ropppngi Minato-Ku Tokyo 106, Japan
Tel : (81)-3-3402-6231- Fax: (81)-3-3408-8268
E-mail : suzaki@shunji.iis.u-tokyo.ac.jp
Abstract
In Asian countries with rapidly growing population and economy, there may be some possibilities of good shortage triggered by natural/human-induced disasters such as flood and drought. Monitoring agricultural production by remote sensing data is expected to by very helpful for providing country measures as early as possible. To explore the possibility of agricultural production monitoring on the real time basis, the authors examined changes o NDVI values of North Korea.
1. Introduction
In Asian countries with rapidly growing population and economy, there may be some possibilities of food shortage triggered by natural/human-induced disaster such as flood and drought. Monitoring agricultural production by remote sensing data is expected t be very helpful for providing countermeasures as early as possible. UNFAO is also making efforts to cover Asian regions with the network of "early winning system" based on remote sensing images. The objective of this study is to explore the possibility of early warning system based on satellite remote sensing data through the comparison of NDVI values of North Korea of 1992 and 1997.
Fig. 1 North Korea rice production in 90's comparing with other countries (UNFAO)
Table 2. Korea DPR: Cereal balance sheet for 1996/97 (thousand tons) (UNFAO)
| Total Availability |
3032 |
Total Utilization |
4966 |
Import requirement |
1934 |
| -Production |
2874 |
-Food use |
3798 |
-Commercial Imports |
430 |
| -Opening stocks |
158 |
-Feed use |
400 |
-Food assistance (pledged & delivered) |
323 |
| |
|
-Other uses (seed, losses and industrial use) |
452 |
-Uncovered import requirement |
1181 |
| |
|
-Closing stocks |
316 |
|
|
2. Data Acquisition / processing
We use NOAA AVHRR data which we receive at Institute of Industrial Science, University of Tokyo and focus on the data acquired at three p.m. in August 1997 and 1992. For an analysis of the data we use PaNDA (Package for NOAA Data Analysis), free software, which includes radiometric correction and geometric correction. In order to remove the effects of the cloud cover as possible we made 10 day composite of NDVI image by choosing the maximum NDVI value over each 10 day at each pixels. The following formula is applied to the computation of NDVI values.
| NDVI = 260 x |
Ch.2(near infrared)-Ch. 1(visible)
------------------------------
Ch.2 + Ch. 1 |
+ 15 |
This formula has been used by UNEP-GRID(United Nations Environmental Program - Global Resource Information Database). Ch.1 and Ch. 2 respectively denote channel values of ch. 1 (visible) and ch. 2(near infrared) of NOAA AVHRR data. Flowchart of the data processing is presented in Fig. 2.
Fig. 2. Flowchart of the data processing
