* Nikkei trades above 200-day moving average
* Nikkei still down 2.1 percent this week
* Short-selling ratio hit record high on Thurs
By Ayai Tomisawa
TOKYO, Aug 28 (Reuters) - Japan's Nikkei share average surged more than 2 percent on Friday, helped by further gains on Wall Street after strong U.S. economic data buoyed sentiment that had been shaken by fears of a China-led global economic slowdown.
The Nikkei was up 2.3 percent at 19,005.83 points by midmorning after climbing as high as 19,047.68, rising above its 200-day moving average for the first time in five days. The Nikkei's 200-day moving average stood at 19,031 as of Thursday market close.
Commodity-related stocks led the rally after oil prices rocketed overnight and other commodity prices soared, with trading houses Mitsubishi Corp soaring 7.2 percent and Mitsui & Co jumping 6.2 percent.
Toho Zinc jumped 9.2 percent and Sumitomo Metal Mining surged 8.2 percent after prices of copper and zinc scored the biggest one-day gains in over two years.
Data on Thursday showed that the U.S. economy grew 3.7 percent in the second quarter - much faster than the previous estimate of 2.3 percent.
Also supporting sentiment is the prospect that a September U.S. rate hike was unlikely, which fuelled optimism that the worse of recent market turmoil may be over.
"For now, the majority of investors seem to think that the imminent U.S. rate hike is unlikely," said Hikaru Sato, a senior technical analyst at Daiwa Securities. "But because U.S. yields are rising, there still are some bets that the Fed would raise rates so we shouldn't be overly optimistic."
The short-selling ratio on Thursday was a record high of 39.8 percent, according to the Tokyo Stock Exchange.
Traders said that the high ratio signals that investors are still on edge.
Exporters rose, with Toyota Motor Corp gaining 3.5 percent, Honda Motor Co advancing 4.8 percent and Panasonic Corp adding 3.9 percent.
Bucking the strength, airline stocks languished on concerns that fuel prices will soon go up after oil prices soared more than 10 percent on Thursday and posted the biggest one-day gain in more than six years.
Japan Airlines Co dropped 1.2 percent and ANA Holdings Inc declined 0.8 percent.
For the week, the Nikkei has dropped 2.1 percent so far.
The broader Topix gained 2.3 percent to 19,005.36 and the JPX-Nikkei Index 400 advanced 2.6 percent to 13,852.73. (Editing by Kim Coghill)